Thomas H. Heaton

Tom Heaton

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Professor of Geophysics and Professor of Civil Engineering

Director of the Earthquake Engineering Research Laboratory

Ph.D., 1978, Geophysics, California Institute of Technology
B.S., 1972, Physics, Indiana University


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Strong Ground Motion Research

Although smaller earthquakes are far more numerous, large earthquakes (M > 7.5) account for most of the slip in plate tectonics. That is, the number of earthquakes generally decreases by a factor of ten for each unit increase in magnitude, but the energy of an individual earthquake increases by a factor of 32 with each unit increase in magnitude. If we assume that M 8.0 is the largest earthquake magnitude that an earthquake can have in California, then there is three times as much radiated energy in the M 7 to 8 earthquakes as there is in all other earthquakes smaller than M 7. Therefore, we see that although large earthquakes are infrequent, they are the major actors in plate tectonics; in this sense, large earthquakes are inevitable.

What will happen when one of these large magnitude earthquakes attacks one of our cities? Of course, the answer to this question depends on the particulars of the earthquake and the capacity of the buildings that are shaken. Even if we could anticipate the magnitude of our future earthquakes, it's still hard to say what shaking the buildings will experience; ground shaking can easily vary by a factor of ten times between sites that are equidistant from an earthquake. In order to deal with the large variability in observed shaking, it has become popular to construct probabilistic models of exceeding a given intensity of shaking (Probabilistic Seismic Hazard Analysis, PSHA). PSHA models are constructed using strong shaking recorded in the past four decades. One of the key questions is how well these records inform us about what will happen in future earthquakes. There are currently enough records to characterize motions that can occur in earthquakes up to about M 7. However, larger earthquakes are so infrequent that there are far too few records to characterize the range of shaking that occurs in great earthquakes (e.g., the 1906 San Francisco earthquake). Therefore PSHA must extrapolate relationships between ground motion and earthquake magnitude to large magnitudes. As currently practiced, most of these extrapolations are based on log-normal statistical models (Gaussian distributions) that are commonly used in actuarial science. While this type of statistics may be appropriate for high-frequency ground shaking (peak ground acceleration), low-frequency ground motions are best described with heavy-tailed power laws (sometimes referred to as a Pareto Distribution). Unfortunately, the current practice of extrapolating into the future using log-normal statistics may seriously underestimate the size of long-period ground motions that will occur in future earthquakes.

My research is in both earth sciences (understanding the physics of shaking) and in earthquake engineering (understanding the physics of yielding buildings). There seems to be an inconsistency between earth scientists and earthquake engineers about the significance of large magnitude earthquakes. Much of our work is aimed at a more complete understanding of the nature of ground shaking close to large earthquakes. That is, ground motions from large earthquakes are simulated by propagating waves through 3-dimensional earth structure models. The models produce realistic estimates of the large displacements (several meters in several seconds) that occur in great earthquakes. While accelerations that are associated with these large displacements may not be large enough to cause failure of strong, shear-wall structures (most of California's construction of 3 stories and less), they may cause severe deformations in flexible buildings (almost all buildings taller than 8 stories are flexible) that rely heavily on ductility for their performance in large earthquakes. This work is closely coordinated with Prof. John F. Hall.

We (Jing Yang) also investigated the potential performance of steel moment-resisting-frame buildings in large subduction zone earthquakes.  We have simulated the deformations and damage that would have occurred to such buildings in the M 8.3 Tokachi-Oki earthquake (2003).  Although there we no such buildings present on the island of Hokkaido during this earthquake, there were 275 strong motion records which we are using as the basis of our study.  In addition, we are using this data as the basis of an empirical Green’s function study of the potential effects of a giant (M>9) subduction earthquake on high-rise buildings in the cities of Seattle, Portland, and Vancouver. Our simulations indicate that long-period shaking from a giant Cascadia earthquake will last for three to five minutes. Furthermore, long-period period (2 to 8 sec.) ground motions will be strongly amplified in the Seattle basin. Because the down-dip extent of rupture on the subduction zone is unknown, we have simulated motions for three different cases: 1) the rupture is confined to the offshore part of the zone, 2) rupture extends about 20 km east of the coast, and 3) rupture extends to the eastern margin of the Olympic peninsula. Shaking from cases 2 and 3 is strong enough to induce large nonlinear deformations for building simulations in the Seattle basin. In many of the simulations, collapse is indicated. It seems clear that current design procedures for Seattle high-rises do not assure collapse prevention in the case of a giant Cascadia earthquake. This work is described in Jing Yang's Ph.D. dissertation ( pdf) and in a talk given at the 2009 meeting of the Seismological Society of America (pdf).

We (Anna Olsen, USGS, and Shiyan Song) are also studying the performance of steel moment-resisting-frame buildings and base-isolated buildings in simulations of large crustal earthquakes in California.  These include simulations of the 1906 San Francisco earthquake (collaboration with Brad Aagaard) and simulations of several plausible earthquakes in the Los Angeles Basin. We show that a repeat of the 1906 earthquake may cause irreparable damage or collapse of many tall buildings in San Francisco. The collapse hazard is about five times higher for steel frame buildings with brittle welds. This includes most buildings constructed before the 1994 Northridge earthquake, which revealed this flaw in building construction. Although traditional response spectra are best for predicting building deformation for moderate shaking, our analysis indicates that a combination of peak ground velocity and peak ground displacement is actually a better predictor of building collapse. We also show that base-isolated buildings that are typical of the current state of the art are likely to experience violent impacts with their foundations for many sites within 10 km of the San Andreas fault.

We (Masumi Yamada and Anna Olsen) show that the seismic hazard from long-period near-source ground motions is fundamentally different from the seismic hazard from short-period motions (pdf). While the hazard from near-source short-period motions can be well characterized by a log-normal distribution, the hazard from near-source long-period motions seems best described by a log-uniform distribution, which is a type of heavy-tailed Pareto distribution. Unfortunately the uncertainties introduced by such a distribution are very high. Current procedures in performance based earthquake engineering may not appropriately capture the risk associated with large earthquakes and long-period buildings.

The PhD work of Shiyan Song shows that the current practice of characterizing the intensity of ground shaking with 5% damped response spectral acceleration at the elastic period of a building does a poor job of predicting collapse of buildings when compared to non-linear finite element analysis of steel special-moment-resisting-frame buildings. A better approach to equivalent linear analysis is to assume a free period that is lengthened by square root of the ductility, and damping that is on the order of 70% of critical. That is, buildings that are undergoing large plastic strains are very poor resonators. We show that when the 70%-damped spectral acceleration at 3/2 the elastic period exceeds the pushover yield strength of a building, then the building is likely to collapse. We show how this measure of ground motion is related to peak ground velocity and peak ground displacement that is used by Olsen, Hall, and Heaton.

Base-Isolated Buildings

It seems that seismic isolation systems are becoming very popular for buildings in seismic regions. While the potential benefits of isolation systems are well documented (reduced inertial forces for the structure and contents of a building), it seems that very little attention is given to the fact that base-isolated buildings may perform poorly in the largest earthquakes. That is, there is a maximum displacement that can be accommodated by isolators. These displacement maxima are determined by a number of factors, but especially the diameter of the isolator. Many recent designs have maximum isolator displacements of 40 to 50 cm. If the ground moves moves more than the allowable isolator displacement, and if the motion occurs fast enough, then the building is likely to experience an impact between its structure and a concrete wall in the foundation. Such impacts are likely to damage the structure of the building and to cause very high acceleration transients within the building. For example, the International Terminal of San Francisco International Airport is base isolated and it has a maximum isolator displacement of 40 cm and a 3 sec. equivalent period of the isolators. The structure is located about 4 km from the San Andreas fault that experienced 3.5 m of slip in the 1906 earthquake. Simulations of ground motions for the 1906 earthquake produce ground motions at SFO that clearly exceed the design for this award-winning structure (pdf). Amazingly, it is almost never mentioned that a repeat of the 1906 earthquake would probably cause severe damage to this structure.

The San Bernardino Justice Center is another example of an award-winning base-isolated structure. In this case, 5-sec triple pendulum isolators are employed to isolate this 11-story building that is located 8 km from the San Andreas fault. The maximum isolator displacement of 110 cm may be far too small if this fault experiences large slip in a future large earthquake that most earth scientists consider to be likely within the next century (the ShakeOut Scenario assumes slips as large as 12 m on some fault segments). Again, available documents only discuss the benefits of the isolation system, and the fact that the system will result in a violent collision between the building and its foundation is not mentioned. It appears to me that something is seriously amiss with the current situation. Structural engineers are advising clients that installation of seismic isolators will greatly decrease their vulnerability, even though it seems clear that base-isolated structures are destined to experience violent impacts in future large earthquakes.

I suspect that much of the miscommunication between structural engineers and the earth scientists is the result of the National Seismic Hazard maps produced by the USGS. These maps provide estimates of peak shaking intensity for specified time periods (e.g. 10% in 50 years), where the shaking intensity is described with either peak ground acceleration (pga), or response spectral acceleration (sa) at periods of 0.2 s and 1.0 s. Unfortunately, none of these shaking intensity parameters provide any information about the maximum displacement required of a base isolator. That is best described by response spectral displacement in the period band from 2 to 5 seconds. The reason that there are no National Seismic Hazard maps for these parameters is that it is very difficult to compute the statistical properties of long-period ground motions. These long-period ground motions are sensitive to the size of the slip on nearby faults, basin resonance phenomena, and directivity effects. Most seismic hazard calculations assume that shaking statistics are described by log-normal variations about mean values that are simple functions of earthquake magnitude and the distance between the site and a potential rupture. Unfortunately, the statistics of long-period ground motions are definitely not log-normal; they are best described as a Pareto Distribution in which infrequent events control the exceedence probabilities that are important for base-isolated buildings (see Yamada, Olsen, and Heaton). This is a critically important issue; we are commonly told that these long-period structures are designed for the 2,500-yr ground motion, when in fact, large earthquakes that will occur in the next several centuries are likely to cause severe damage (or collapse) with these important structures.

Earthquake Rupture Physics and Crustal Stress

Much of the deformation of the Earth's crust occurs as earthquake rupture. Therefore, it is of critical importance to understand the fundamental dynamics of earthquake rupture to understand the stress state of the crust. A short description of the problem can be found at Live Science. We are particularly interested in understanding the origins of spatially heterogeneous slip in earthquakes.  There is compelling evidence that slip in earthquakes and stress in the Earth’s crust are spatially heterogeneous, and perhaps fractal. We have been pursuing two different approaches to understand the dynamic properties of this system.

The first approach is a long-standing collaboration with Dr. Brad Aagaard (USGS, Menlo Park) and it consists of constructing 3-dimensionional finite-element models of the Earth's crust, which are controlled by dynamic friction on fault planes. The models include the effects of gravity so that crustal stresses are consistent with the topography of the Earth's surface and density variations in the crust. The models allow us to follow the partitioning of elastic and gravitational potential energy into radiated seismic waves, fracture energy, and frictional heating on faults. Using estimates or bounds on wave energy, fracture energy, and heat energy, it is possible to put bounds on crustal deviatoric stress.

Despite steady progress in simulating dynamic earthquake ruptures, there are limitations of this approach to understanding the dynamic properties of the crust.  In particular, recent experiments in dynamic friction suggest that there are rapid transitions between high static friction (>200 MPa at 10 km depth) and very low dynamic friction (<5 MPa).  These strong transitions in friction point to very localized slip pulses that propagate unsteadily along faults. Unfortunately, simulation of dynamic rupture with these friction laws requires enormous spatial grids with very fine time resolution. We (Jing Liu-Zeng) have constructed fractal models of slip that are compatible with observations of slip vs. rupture length scaling and also with earthquake frequency vs. magnitude statistics.

In addition we (Deborah Smith) have constructed a 3-dimensional fractal model of tensor stress that we use to simulate catalogs of earthquake locations and focal mechanisms.  This model predicts that traditional inversions of focal mechanism catalogs for average stress orientation may provide results that are seriously biased towards the orientation of the stress rate function.  It also predicts that the strength of the crust depends on the length scale over which failure occurs.  We (Ahmed Elbanna) are currently investigating the statistical relationship between fractal stress and fractal slip. Ahmed Elbanna, Nadia Lapusta, and I have been able to show that there are no steady-state solutions to the problem of a propagating slip pulse that is the result of pure rate-weakening friction. Unfortunately, it is not technically feasible to numerically simulate the long-time behavior of a sliding surface subject to pure rate-weakening friction. In order to gain insight into this challenging dynamics problem, Ahmed Elbanna and I studied the behavior of pure rate weakening friction for a simple spring-block-slider model. We found that this system is inherently a chaotic system that self organizes into complex prestress state that appears to be fractal in nature (wavenumber spectra described by power laws). We show that any rational definition of the material strength of this system depends on the length scale over which the strength is measured. In particular, larger systems operate a smaller average stresses than smaller systems. Furthermore, the scale dependence of the strength is related to the b-value of the seismic events in the system. b-values approaching 1.5 correspond to an interface that slips during many small magnitude events. On the other hand, b-values less than 0.5 correspond to systems that primarily slip in large events. We call the small b-value systems, "brittle" and they have strong length scale dependence with increasing size. The 1.5 b-value systems are more ductile and they have weak length scale dependence of strength. You can read about these interesting findings in Elbanna's PhD thesis pdf.

Perhaps the most exciting development of our work on chaotic spring-block sliders is the discovery of the Pulse-Energy Equation pdf. Full numerical solution of the spring-block-slider model is very time consuming. We derived a simple 1-d ordinary differential equation that tracks energy changes in a system as a slip pulse propagates along the interface. This is a new class of equation that closely mimics the full numerical solution. Furthermore, it seems to work over an extreme range of time and spatial scales. Best of all, when it is run over a long time scale (many events), it self organizes into a state that is similar to the state that is the result of the full numerical solution. I view discovery of this equation as a fundamental breakthrough.

Earthquake Warning Systems

I have had a decades-long interest in developing automated systems to utilize seismic data to help society to respond during an earthquake crisis. In 1985, I published "A model for a seismic computerized alert network," which described a framework for developing a system to alert users of the arrival time and shaking amplitude of seismic waves that were propagating towards a particular user. That paper generated widespread interest and it was the basis for many of the design requirements for the Southern California Seismic Network (SCSN). Through the years, I have collaborated with numerous colleagues to try to make the seismic computerized alert network (SCAN) into reality. I worked with Jim Mori (USGS), Hiroo Kanamori (Caltech), and Egill Hauksson (Caltech) to design and deploy the Southern California Seismic Network (SCSN). I also worked with David Wald (USGS) to develop the first versions of ShakeMap, which is now an important emergency management tool that is supported by the NEIC of the USGS. More recently, I have collaborated with Richard Allen (UCB) and Egill Hauksson (Caltech) to develop CISN ShakeAlert, which is currently an operating demonstration system that uses CISN data to alert dozens of test users about shaking that they are about to experience.

My role in ShakeAlert development has focused on the development of new automated algorithms that analyze data and then predict the characteristics of impending shaking. I worked with Georgia Cua to develop a Bayesian statistical framework that incorporates prior information with real-time seismic information to produce a probabilistic model of future shaking. This work was the basis of the Virtual Seismologist (VS) framework that is currently being developed corroboratively with ETH, Zurich (John Clinton and Yannik Behr). The Virtual Seismologist (VS method) is based on the type of robust analysis that a human would perform if they had the time.  We use envelopes of acceleration, velocity, and displacement as the basic data input to a Bayesian framework that also incorporates other types of information (e.g., topology of the seismic network, recent seismic activity). I am working with Lucy Yin to incorporate current seismicity information (e.g., potential foreshocks) into the analysis. I am also working with Gokcan Karakus on developing an algorithm that checks the match between envelopes of recorded strong motion data and predictions that result from the alerting system. This promises to significantly improve the reliability of the system. I have also been working with Men Andrin-Meier (ETH) to develop a Bayesian inference algorithm (the Gutenberg Algorithm) to statistically analyze the output of real-time filter banks that are an efficient type of wavelet transform.  The Gutenberg Algorithm promises to make seismic alerting systems significantly faster than existing algorithms; the filter banks deliver the vital information with delays that approach the theoretical minimum.

Most existing algorithms are designed to determine the location and magnitude of a point source that best explains available data. However, in earthquakes larger than M 7, it is critical to know the spatial extent of a long rupture. We are also working on methodologies that will provide real-time estimates of rupture geometry and fault slip. Masumi Yamada and I extended the VS framework to include the analysis of time-evolving finite ruptures. We developed algorithms that determine whether or not a station is located in the near-source region of a rupture (pdf). This work was extended in a collaboration with Maren Bose to develop the FindEr algorithm (pdf) that uses peak acceleration data to track the propagation of long ruptures. Maren Bose and I also developed a real-time algorithm that estimates the spatio-temporal distribution of slip by projection of peak ground displacement data (GPSlip). This work was based on research with Masumi Yamada. One of the challenges of seismic alerting is to estimate the probability of future shaking for earthquakes that are still propagating. More recently, I have been collaborating with Maren Bose and Sarah Minson (USGS) to develop a Bayesian inference framework to combine the information that is coming from numerous algorithms. This is a challenging problem in which we must determine which information is significant and independent of other information. This framework is currently being developed into C++ computer code called Finder-BEFORES.

It's one thing to provide rapid alerting information and it's quite another thing to use the information to make the best decisions in an ongoing emergency (kind of like battlefield management). I have been collaborating with James Beck and Stephen Wu to develop a framework (ePAD) for deciding when to trigger automated actions based on stream of information broadcast by the ShakeAlert system. For example, some actions may be costly to implement and it may be appropriate to delay an action until enough data is analyzed to insure that the ground motion prediction is reliable. Elevator control is an obvious candidate for earthquake alerting. The motions of tall buildings are often very different from the motions at the base of a building. For example, tall buildings (20 stories) in Mexico City resonated sympathetically with resonance of the lake beds underlying Mexico City in the 1985 Michoacan earthquake. People on the ground adjacent to buildings only experienced very mild shaking while nearby tall buildings swayed violently and often collapsed. The combination of a large magnitude event located some 200 miles from Mexico City would have allowed a prediction that tall buildings would sway for over a minute in this event. Unfortunately, earthquake alerting would probably not have saved people who were crushed by the collapsing buildings, a system could predict that the buildings would experience a long duration of swaying motion. Ming Hei Cheng and I have proposed a methodology to predict the nature of shaking in tall buildings based on the known resonant period of a building, the location of the building relative to the earthquake, and the location of a person in the building (pdf). Clearly, some day in the future, residents of tall buildings will be told by their smart phones about the characteristics of the shaking that they are about to experience.

Caltech, the Univ. of Calif. at Berkeley (UCB), and Univ. of Washington (UW), the USGS, the California Office of Emergency Services, and ETH Zurich are actively developing the ShakeAlert system (pdf), which is a working demonstration project to develop earthquake early warning on the West Coast of the US. This system has been funded by the U.S. Geological Survey and the Gordon and Betty Moore Foundation. More information about Caltech's role can be found on our Caltech earthquake alerting website.

Studies of Building Vibrations

The overall goal of this research is to develop tools and a framework to describe the structural properties of buildings. In particular, there is growing interest in developing a building rating system. That is, interested individuals would be able to discover pertinent information about the structural integrity of individual buildings so that they could make more informed decisions about whether of not to occupy that building. While knowledge of the building's structural design is critical to understanding its seismic resistance (see the PhD research of Kenny Buyco), it is also of critical importance that we are able to characterize and monitor the vibrational characteristics of individual buildings. This means that we must extend our seismic networks so that they also document the vibrations of buildings.

We (Monica Kohler) are investigating the vibrations of buildings that are excited by a wide number of sources, including wind, explosions, machinery, and earthquakes of all sizes.  We have installed an advanced 24-bit, 140 dB seismic station that continuously records the 9-story Millikan Library on the Caltech campus, a building which has been the source of several interesting mysteries. For example, when the building's fundamental modes (north-south, east-west, and torsion) are excited by a 1-hp eccentric shaker operated on the building's roof, harmonic seismic waves are observed at the building's eigen-frequencies throughout the Pasadena area; they can even be detected on seismometers just north of the US-Mexican border, which is about 250 km away (see Javier Favela’s dissertation).

Another interesting mystery of Millikan Library is the fact that the natural frequencies of the fundamental modes (north-south, east-west, and torsion) all increase by several percent just following significant rain storms.  These increases in frequency slowly decrease over a period of several days.  We have been using advanced time-frequency representations (the Wigner-Ville distribution) to investigate how these natural frequencies change during shaking to both damaged and undamaged buildings (see Casey Bradford’s dissertation).

Vanessa Heckman, Monica Kohler, and I developed a novel new technique to detect and locate fracture of moment resisting connections in steel buildings. High-frequency waves (> 100 Hz) are radiated throughout a building frame when fracture of brittle weld occurs. Although these welded connections are important to the integrity of a steel building, it is currently very difficult (expensive) to detect when connections fail. Our technique uses seismic records to detect and locate these weld fractures.

Obtaining recordings of ground motion have been facilitated by the development of crowd-sourced seismic networks. Traditional seismic networks consists of instruments that are installed and maintained by personnel working for the network operator. In contrast, seismic stations in a crowd-sourced network are operated by others. These others can include volunteers or they may also include professionals at collaborating agencies (e.g., rail transportation agencies, utilities, etc.). The fact that all smart phones have mems accelerometers means that we may one day receive seismic records from millions of cell phones. These records can give us a much more detailed picture of the seismic wavefield as it propagates through California. The most revolutionary aspect of crowd sourced networks is likely to come from building monitoring. Some day in the not-too-distant future there will be a time when the vibrational history of virtually every building will be recorded for significant earthquakes. An additional benefit of the Community Seismic Network is that it will send many real-time estimates of shaking intensity. This will allow for the construction of far more detailed ShakeMaps than is currently feasible. Furthermore, real-time shaking messages will greatly help to make ShakeAlert faster and more reliable.

Caltech Civil Engineers (Monica Kohler and Ming Hei Cheng) are collaborating with Caltech Seismologist, Prof. Rob Clayton, and Caltech Computer Scientist, Prof. K. Mani Chandy, to develop the Community Seismic Network (CSN). This exciting project is funded by the Gordon and Betty Moore Foundation. Currently, there are more than 500 3-component accelerometers that continuously telemeter acceleration data. 100 of these are located on the campuses of the Los Angeles Unified School District.


Nineke Oerlemans, 1999, MS in Geophysics from Utrecht Univ. (co-advised with H. Paulssen), Sorting Source Parameters to Produce Coherent Record Sections pdf
Brad Aagaard, Ph.D. 2000, CE (co-advised with John Hall); Finite-element simulations of earthquakes. pdf
Javier Favela, Ph.D. 2004, Geophysics, Energy radiation from a multi-story building. pdf
John Clinton, Ph.D. 2004, CE Modern digital seismology - instrumentation, and small amplitude studies in the engineering world. pdf
Georgia Cua, Ph.D. 2004, CE Creating the Virtual Seismologist: developments in ground motion characterization and seismic early warning pdf
Deborah Smith, PhD 2006, Geophysics, A new paradigm for interpreting stress inversions from focal mechanisms; how 3D stress heterogeneity biases the inversions toward the stress rate pdf
Casey Bradford, Ph.D. 2006, CE, Time-frequency analysis of systems with changing dynamic properties pdf
Masumi Yamada, Ph.D. 2007, CE, Early warning for earthquakes with large rupture dimension. pdf
Anna Olsen, Ph.D., 2008,CE, Steel moment-resisting frame responses in simulated strong ground motions : or how I learned to stop worrying and love the big one. pdf
Jing Yang, Ph.D., 2009, CE, Nonlinear responses of high-rise buildings in giant subduction earthquakes. pdf
Ahmed Elbanna, Ph.D.,2011, CE, Pulse-like ruptures on strong velocity weakening interfaces: dynamics and implications. pdf
Shiyan Song, Ph.D., 2013, CE, A new ground motion intensity measure, peak filtered acceleration (PFA), to estimate collapse vulnerability of buildings in earthquakes. pdf
Vanessa Heckman, Ph.D., 2014, CE, Damage detection in civil structures using high-frequency seismograms. pdf
Ming Hei Cheng, Ph.D., 2014, CE  New applications that come from extending seismic networks into buildings. pdf
Matthew Faulkner, Ph.D., 2014, CS, (co-advised with Mani Chandy and Andreas Kraus), Community sense and response systems. pdf
Ramses Mourhatch, Ph.D., 2015, CE, (co-advised with Swaninathan Krishnan) Quantifying Earthquake Risk of Tall Steel Braced Frame Buildings Using Rupture-to-Rafters Simulations. pdf
Hemanth Siriki
Ph.D., 2015, CE, (co-advised with Swaminathan Krishnan), Quantifying Earthquake Risk of Tall Steel Moment Frame Buildings Using Rupture-to-Rafters Simulations. pdf
Men-Andrin Meier,
ETH (Zurich), Ph.D., GP, 2015, (co-advised with Stephan Wiemer and John Clinton), Advancing Real-Time Risk Mitigation: Probabilistic Earthquake Early Warning and Physics Based Earthquake Triggering Models.
Christopher Janover,
Ph.D., 2015, CE, Steel Converter and Caltech Virtual Shaker: Rapid Nonlinear Cloud-Based Structural Model Conversion and Analysis.
Gokcan Karakus, CE (earthquake early warning) Developing a Reality Check algorithm for seismic alerting systems. How to use waveform envelopes to make seismic alerting more reliable.
Lucy Yin, CE (earthquake early warning) Developing Bayesian prior models to make alerting systems faster
Anthony Massari,
CE Investigating steel structures by combining advanced nonlinear analysis models with in situ sensor technologies in existing buildings to access the design, health and robustness of various lateral systems to hazards.
Kenny Buyco, CE The building code requirements for tall buildings have been changing over the past several decades. Buyco is studying how the capacity of steel moment-resisting-frame buildings vary with construction date and location.
Becky Roh, CE, Seismic alerting systems

Courses Taught

ME 35c Statics and Dynamics. 9 units (3-0-6); Prerequisites: Ma 1 abc, Ph 1 abc, Introduction to analysis of stress and strain in engineering.
ME 65. Mechanics of Materials. 9 units (3-0-6); Prerequisites: AM 35 abc, Ma 2 ab. Introduction to continuum mechanics, principles of elasticity, plane stress, plane strain, axisymmetric problems, stress concentrations, thin films, fracture mechanics, variational principles, frame structures.
CE 151a/ME 66. Dynamics and Vibrations. 9 units (3-0-6);  Prerequisites: AM 35 abc, Ma 2 ab. Introduction to dynamics in discrete multi-degree-of-freedom systems. mass-spring systems, mechanical devices, generalized coordinates, Lagrange's equations, Hamilton's principle, normal modes, nonlinear systems, bifurcations, and dynamic chaos.
CE/Ge 181 ab. Engineering Seismology. 9 units (3-0-6);  Characteristics of potentially destructive earthquakes from the engineering point of view. Determination of location and size of earthquakes; magnitude, intensity, frequency of occurrence; engineering implications of geological phenomena, including earthquake mechanisms, faulting, fault slippage, and effects of local geology on earthquake ground motion. (CE/GE 181 page)

Awards and Honors

Seismological Society of America (President 1993-1995)
1995 Meritorious Service award from the U.S. Dept. of Interior
2007 Fellow of the American Geophysical Union

  1. Alewine, R.W., and Heaton, T.H. 1973, Tilts associated with the Pt. Mugu earthquake, in Kovach, R.L., and Nur, A., eds..., Conference on tectonic problems of the San Andreas fault system, Stanford, California, 193, Proceedings: Stanford Univ. Pubs. Geol. Sci., v. 13,p. 94-103.
  2. Ellsworth, W., R. Campbell, D. Hill, R. Page, R. Alewine, T. Hanks, T. Heaton, J. Hileman, H. Kanamori, B. Minster, J. Whitcomb, 1973, Point Mugu, California, earthquake of 21 February 1973 and its aftershocks, Science, v. 182, 1127-1129. pdf
  3. Heaton, T.H., 1975, Tidal triggering of earthquakes: Geophysical Journal of the Royal Astronomical Society, v. 43, p. 307-326.
  4. Heaton, T.H., and Helmberger, D.V., 1977, Predictability of strong ground motion in the Imperial Valley: Modeling the M 4.9, November 04, 1976 Brawley earthquake: Seismological Society of America Bulletin, v. 68, no. 1, p. 31-48. pdf
  5. Heaton,T.H., and Helmberger, D.V., 1977, A study of the strong ground motion of the Borrego Mountain, California, Earthquake, Bulletin of the Seismological Society of America, v 67, 315-330. pdf
  6. Heaton, T.H., and Helmberger, D.V., 1978, Synthesis of San Fernando strong-motion records: National Science Foundation Seminar Workshop on Strong Ground Motion, San Diego, 1978, Proceedings, p. 52-55.
  7. Heaton, T.H., 1978, Generalized ray models of strong ground motion: Ph.D. Thesis, California Institute of Technology, Pasadena, Cal if., 300 p. pdf
  8. Heaton, T.H., and Helmberger, D.V., 1979, Generalized ray models of the San Fernando earthquake, Bulletin Seismological Society of America, v. 69, no. 5, p. 1311-1341.pdf
  9. Anderson, J.G., and Heaton, T.H., 1980, Aftershock accelerograms recorded on a temporary array in Johnson, C.E., Sharp, R., and Rojan, C., eds..., The Imperial Valley Earthquake: U.S. Geological Survey Professional Paper No. 1254, pp 443-451.
  10. McNutt, M., and Heaton, T.H., 1981, An evaluation of the seismic window theory: California Division of Mines and Geology, California Geology, January 1981, p. 12-16.
  11. Heaton, T.H., 1982, The 1971 San Fernando earthquake; a double event: Bulletin of the Seismological Society of America, v. 72, no. 6, p. 2037-2062.pdf
  12. Heaton, T.H., 1982, Tidal triggering of earthquakes, Bulletin of the Seismological Society of America, v. 72, no. 6, p. 2181-2200. pdf
  13. Anderson, J and T. Heaton, 1982, Aftershock accelerograms recorded on a temporary array, The Imperial Valley, California, Earthquake of October 15 (1979), 443-451.
  14. Heaton, T.H., Anderson, J.G., and German, P.T., 1983, Ground failure along the New River caused by the 15 October 1979 Imperial Valley earthquake sequence, Bulletin of the Seismological Society of America, vol. 73, no. 4, 1161-1171.pdf
  15. Hartzell, S.H., and Heaton, T.H., 1983, Inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 Imperial Valley, California, earthquake, Bulletin of the Seismological Society of America, vol. 73, no. 6, 1153-1184. pdf
  16. Hartzell, S.H, and Heaton, T.H., 1983, Teleseismic mechanism of the May 02, 1983 Coalinga, California, earthquake from long-period P-waves, in Bennett, J.H., and Sherburne, R.W., eds..., The 1983 Coalinga, California Earthquakes, Calif.. Div. Mines and Geology Special Publications 66, 241-246.
  17. Moslem, K, Amini, A. Kontic, B., Anderson, J.G., and Heaton, T.H., 1983, Accelerograms from the Mammoth Lakes, California earthquake sequence of May-July, 1980 recorded on a temporary array, University of Southern California Department of Civil Engineering Report no. CD83, 64 p.
  18. Heaton, T.H., and Kanamori, H., 1984, Seismic potential associated with subduction in the northwestern United States, Bulletin of the Seismological Society of America, v. 74, no. 3, pp. 933-941.pdf
  19. Liu, H.L., and Heaton, T.H., 1984, Array analysis of the ground velocities and accelerations from the 1971 San Fernando California, earthquake, Bulletin of the Seismological Society of America, v. 74, no. 5, pp. 1951-1968. pdf
  20. Heaton, T.H., 1985, A model for a seismic computerized alert network, Science, v.228, pp. 987-990 pdf
  21. Heaton, T.H., and Kanamori, H., 1985, Reply to Hemendra Acharya on his comments on "Seismic potential associated with subduction in the northwestern United States", Bulletin of the Seismological Society of America., v.75, pp.891-892. pdf
  22. Hartzell, S.H., and Heaton, T.H., 1985, Teleseismic time functions for large shallow Subduction zone earthquakes, Bulletin of the Seismological Society of America , v. 75, pp. 965-1004. pdf
  23. Heaton, T.H., and P,D. Snavely, Jr., 1985, Possible tsunami along the coast of Washington inferred from Indian traditions, Bulletin of the Seismological Society of America, v. 75, pp. 1455-1460.pdf
  24. Hartzell, S.H., and Heaton, T.H., 1985, Rupture history of the 1984 Morgan Hill, California, earthquake from the inversion of strong motion records, Bulletin of the Seismological Society of America, v.76, pp. 649-674. pdf
  25. Heaton, T.H., Tajima. F., and Mori, A.W., 1986, Estimating ground motions using recorded accelerograms, Surveys in Geophysics, V. 8, pp 25-83. pdf
  26. Heaton, T.H., and Hartzell, S.H., 1986, Source characteristics of hypothetical subduction earthquakes in the northwest United States, Bulletin of the Seismological Society of America, V, 76, pp. 675-708. pdf
  27. Heaton, T.H., and Hartzell, S.H., 1986, Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest, U.S. Geol. Surv. , Open-File Report 86-328, 70 p. link
  28. Heaton, T.H., and Hartzell, S.H., 1987, Earthquake hazards on the Cascadia subduction zone, Science, v. 236 (4798), 162-168. pdf
  29. Heaton, T.H., 1987, Anomalous seismicity in the San Diego coastal region. Proceedings of workshop XXXVII, Physical and Observational Basis for Intermediate-Term Earthquake Prediction, Eds. K. Aki and W. Stuart, U.S. Geological Surv. Open-File Report 87-591, 667-681.
  30. Hartzell, S.H., and Heaton, T.H., 1988, Failure of self-similarity of large shallow subduction earthquakes, Bull. Seism. Soc. Am., 78, 478-488. pdf
  31. Heaton, T.H., and Hartzell, S.H., 1988, Earthquake Ground Motions, Ann. Rev. Earth Planet. Sci., v.16, pp 121-145.
  32. Heaton, T.H., and Hartzell, S.H., 1989, Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest, Pure and Applied Geophysics, 129, 131-201.pdf
  33. Heaton, T.H., and Heaton , R.E., 1989, Static deformations from point forces and force couples located in welded elastic Poissonian half-spaces: implications for seismic moment tensors, Bull. Seism. Soc. Am., 79. 813-841. pdf
  34. Heaton, T.H., and Heaton , R.E., 1989, Erratum: Static deformations from point forces and force couples located in welded elastic Poissonian half-spaces: implications for seismic moment tensors, Bull. Seism. Soc. Am., 79, 1056. pdf
  35. Heaton, T.H., Anderson, D., Arabasz, W., Buland R., Ellsworth, W., Hartzell, S., Lay, T., Spudich, P., 1989, National Seismic System Science Plan, U.S. Geol. Surv. Circular. 1031, 42p. link
  36. Hartzell, S.H., and Heaton, T.H., 1989, The fortnightly tide and tidal triggering of earthquakes, Bull. Seism. Soc. Am., 79, 1282-1286. pdf
  37. Heaton, T.H., and Jones, L.M., 1989, Seismological research issues in the San Diego region, Proceedings of SCEPP Workshop on "The seismic risk in the San Diego region: special focus on the Rosa Canyon fault system", Editor, G. Roquemore, 42-49. pdf
  38. Wald, D.J., D.V. Helmberger and T.H. Heaton, Rupture model of the 1989 Loma Prieta earthquake from the inversion of strong-motion and broadband teleseismic data, Bulletin of the Seismological Society of America, v. 81 (5), 1540-157
  39. Hartzell, S.H., and Heaton, T.H., 1990, Erratum; The fortnightly tide and tidal triggering of earthquakes, Bull. Seism. Soc. Am., 90, 504-505. pdf.
  40. Kanamori, H., Mori, J., and Heaton, T.H., 1990, The December 03, 1988, Pasadena earthquake (ML = 4.9) recorded with the very-broad-band system in Pasadena, Bull. Seism. Soc. Am., vol 80, 483-487.pdf
  41. Heaton, T.H., 1990 Evidence for and implications of self-healing pulses of slip in earthquake rupture, Phys. Earth Planet Int., Vol 64. 1-20.pdf
  42. Heaton, T. H., 1990, The calm before the quake, Nature, vol. 343, 511-512. pdf
  43. Hartzell, S., and Heaton, T. H., 1990, Earthquake ground motion at close distances, EPRI/ Stanford/USGS workshop on modeling ground motion at close distances, held in Palo Alto, CA, Sept. 1990, 23p. pdf
  44. Aki, K., T. Henyey, and T. Heaton, 1991, What is the Southern California Earthquake Center?, EOS v. 72, no. 39, p 417 and 421.
  45. Hauksson, E., Jones, L., Mori, J., Clayton, R., Heaton, T., Kanamori, H., and Helmberger, D., 1991, Southern California seismographic network: Report to the U.S. Geological Survey August 21, 1990, U.S. Geol. Surv. Open-File Rept.., 91-38, 51p.
  46. Heaton, T. H., 1991, Seismology in the U.S., 1986-1990, 1991, Reviews of Geophysics, Supplement, U.S. National Report to the IUGG, 659-661.
  47. Kanamori, H., E. Hauksson, and T. Heaton 1991, TERRAscope and CUBE project at Caltech, EOS v. 72, No. 50, p. 564.
  48. Kanamori, H., Mori, J., Anderson, D., and Heaton, T., 1991, Seismic excitation by space shuttle Columbia, Nature, v. 349, 781-782. pdf
  49. Sacks, I., Heaton, T. H., Andrews, R., Savit, C. Toksöz, Tucker, B., Iwan, W., 1991, Real-time earthquake monitoring, Panel on real-time earthquake warning, National Research Council, National Academy Press, Wash., D.C., 52 p.
  50. Wald, D.J., Helmberger, D.V., and Heaton, T. H., 1991, Rupture model of the 1989 Loma Prieta earthquake from the inversion of strong motion and broad band teleseismic data, Bull. Seism. Soc. Am., vol. 81, 1540-1572. pdf
  51. Wald, L.A., and Heaton, T.H., 1991, Lg and Rg waves on the California regional networks from the December 23, 1985 Nahanni earthquake, J. Geophs. Res., vol. 96, 12009-12125.
  52. Agnew, D., K. Aki, A. Cornell, J. Davis, P. Flores, T. Heaton, I. Idriss, D. Jackson, K. McNally, M. Reichle, J. Savage, K. Sieh, 1992, Future Seismic Hazards in Southern California, Phase I: Implications of the 1992 Landers Earthquake Sequence, Southern California Earthquake Center Report, 42p.
  53. Heaton, T., 1992, Seismic threat to the Pacific Northwest, EQE Review, fall issue, 13-18.
  54. Heaton, T., 1992, Are earthquakes predictable?, Proceedings of the Frontiers of Science Symposium, held at the Beckman Center, Irvine, and convened by the National Academy of Sciences, Nov. 1991, 16p. pdf (see also National Academy Press, 1994)
  55. Kanamori, H., J. Mori, B. Sturtevant, D. Anderson, T. Heaton, 1992, Seismic excitation by space shuttles, Shockwaves - an International Journal, V. 2, 89-96.
  56. Kanamori, H., H. Thio, D. Dreger, E. Hauksson, and T. Heaton , 1992, Initial investigation of the Landers, California, earthquake of 28 June 1992 using TERRAscope, Geophys. Res. Let., V. 19, 2267-2270.
  57. Prescott, W.H., J. Dieterich, T. Heaton, T. Holzer, A. Lindh, C. Prentice, P. Spudich, 1992, Report of the Western Region Earthquake Reorganization Task Group, U.S. Geol. Surv. Open-File Rept. xx, about 100 pages.
  58. Sieh, K., L. Jones, E. Hauksson, K. Hudnut, D. Eberhart-Phillips and T. Heaton, April to July 1992, Near-field investigations of the Landers earthquake sequence, Science, V 260 (5105), 171-176.
  59. Landers Earthquake Response Team (20 authors), 1993, Near-field investigations of the Landers earthquake sequence, April-July, 1992, Science, V. 260, 171-176. pdf
  60. Kanamori, H., J. Mori, E. Hauksson, T. Heaton, K. Hutton, and L. Jones, 1993, Determination of earthquake energy release and ML using TERRAscope, Bull. Seism. Soc. Am., V. 83, 330-346. pdf
  61. Wald, D., H. Kanamori, D. Helmberger, and T. Heaton, 1993, Source study of the 1906 San Francisco earthquake, Bull. Seism. Soc. Am., V 83, 981-1019. pdf
  62. Wald, D., and T. Heaton, 1994, Spatial and temporal distribution of slip for the 1992 Landers, California, earthquake, Bull. Seism. Soc. Am., V 84, 668-691. pdf
  63. Scientists of the U.S. Geological Survey and the Southern California Earthquake Center, 1994, The magnitude 6.7 Northridge, California, earthquake of 17 January 1994, Science, V 266, 389-387.
  64. Heaton, T., 1994, Lessons learned from the Northridge Earthquake, Testimony to the Committee on Science, Space, and Technology of the U.S. House of Representatives, March 2, 1994, 7 pages.
  65. Wald, D., and T. Heaton, 1994, A dislocation model of the 1994 Northridge, California, earthquake determined from strong ground motions, U.S. Geological Survey Open-File Report 94-278, 53 pages.
  66. Ellsworth, W., and T. Heaton, 1994, Real-time analysis of earthquakes: Early warning systems and rapid damage assessment, Sensors-the Journal of Applied Sensing Technology, 11 (4), 27-33.
  67. Eguchi, R., J. Goltz, H. Seligson and T. Heaton, 1994, Real-time earthquake hazard assessment in California: the early post-earthquake damage assessment tool and the Caltech-USGS broadcast of earthquakes, Earthquake Engineering Research Institute, v.2, 55-63.
  68. Hall, J.F., T.H. Heaton, M.W. Halling and D.J. Wald, 1995, Near-source ground motion and its effects on flexible buildings, Earthquake Spectra, v.11 (4), 569-605.
  69. Heaton, T., 1995, Overview of seismological methods for the synthesis of strong ground motion, Proceedings of the EPRI/Stanford/USGS workshop on modeling ground motion at close distances, held at Palo Alto, CA, Sept. 1990, 24p.pdf
  70. Heaton, T., J. Hall, D. Wald, and M. Halling, 1995, Response of high-rise and base-isolated buildings to a hypothetical M 7.0 blind thrust earthquake, Science, V 267, 206-211. pdf
  71. Hauksson, E., and T. Heaton, 1995, The Southern California Seismographic Network, Tsunami Warning System Workshop Report, Sept. 14-15, 1994, NOAA, M. Blackford and H. Kanamori, editors, 37-60.
  72. Heaton, T., 1995, Looking back from the year 3,000, Seismological Research Letters, v. 66 (2), 3-4. pdf
  73. Hall, J., T. Heaton, M. Halling, and D. Wald, 1995, Near-source ground motions and its effects on flexible buildings, Earthquake Spectra, 11, 569-605. pdf
  74. Heaton, T., 1995, Urban Earthquakes, Seismological Society of America Presidential Address, Seism. Res. Let., 66, No. 5, 37-40. pdf
  75. Shakal, A.F., M.J. Huang, R.B. Darragh, A.G. Brady, M.D. Trifunac, C.E. Lindvall, D. J. Wald, T. H. Heaton, and J. J. Mori, 1995, Recorded ground and structure motions, Earthquake Spectra, v.11 (S2), 13-96.
  76. Wald, D., T. Heaton and D. Helmberger, 1996, Strong-Motion and Broadband Teleseismic Analysis of the Earthquake for Rupture Process and Hazards Assessment. In: The Loma Prieta, California, earthquake of October 17, 1989--main-shock characteristics. U.S. Geological Survey Professional Paper. No.1550-A. Untied States Government Printing Office , Washington, D.C. , A235-A262. pdf
  77. Wald, D., T. Heaton, and K. Hudnut, 1996, The slip history of the 1994 Northridge, California, earthquake determined from strong-motions, GPS, and leveling-line data, Bull. Seism. Soc. Am., 1b, s49-s70. pdf
  78. Wald, D., T. Heaton, and D. Helmberger, 1996, Strong motion and broad-band teleseismic analysis of the 1989 Loma Prieta earthquake for rupture process and hazards assessment, USGS Prof. Paper 1550-A, 235-262.
  79. Kanamori, H., and T. Heaton, 1996, The wake of a legendary earthquake, Nature, v. 379, 203-204. pdf
  80. Heaton, T., R. Clayton, J. Davis, E. Hauksson, L. Jones, H. Kanamori, J. Mori, R. Porcella, and T. Shakal, 1996, The TriNet Project, Proceedings of the 11th World Conference on Earthquake Engineering, June 23-28, 1996, Acapulco Mexico, published by Pergamon.
  81. Eguchi, R., J. Goltz, H. Seligson, P. Flores, N. Blais, T. Heaton, E. Bortugno, 1997, Real-time loss estimation as an emergency response decision support system: the Early Post-Earthquake Damage Assessment Tool (EPEDAT), Earthquake Spectra, 13, 815-832.pdf
  82. Hall, J., T. Heaton, D. Wald, 1997, Near-source ground motion studies for Northridge and Kobe earthquakes, Final Report, CUREe-Kajima Research Project, phase 2, 1996.9, 105 p.
  83. Kanamori, H., E. Hauksson, and T. Heaton, 1997, Real-time Seismology and real-time earthquake hazard mitigation, Nature, 390, 461-464. pdf
  84. Wald, D., K. Hudnut, and T. Heaton, 1997, Estimation of uniformly spaced near-source broadband ground motions for the 1994 Northridge earthquake from forward and inverse modeling, Proceedings of the CURIEe Northridge Earthquake Research Conference, Los Angeles, August 1997.
  85. Kanamori, H., D. Anderson, and T. Heaton, 1998, Frictional melting during the rupture of the 1994 Bolivian earthquake, Science, 279, 839-842. pdf
  86. Mori, J., H. Kanamori, J. Davis, E. Hauksson, R. Clayton, T. Heaton and L. Jones, 1998, Major improvements in progress for Southern California earthquake monitoring, EOS, 79 (18), 217-221.
  87. Wald, D., and T. Heaton, 1998, Forward and inverse modeling of near-source ground motions for use in engineering response analysis, Structural Engineering Worldwide, Ed. N. Srivastava.
  88. Heaton, T., 1999, Interview with SCEC Scientist, Thomas Heaton, Southern California Earthquake Center Quarterly Newsletter, V. 4, No. 4, 4-10.
  89. Anooshehpoor, A., T. Heaton, B. Shi, and J. Brune, 1999, Estimates of the ground acceleration at Point Reyes Station during the 1906 San Francisco earthquake, Bull. Seism. Soc. Am., 89, 845-853. pdf
  90. Anooshehpoor, A., T. Heaton, B. Shi, and J. Brune, 1999, Reply to comment by J. Zhang and N. Makris on "Estimates of the ground acceleration at Point Reyes Station during the 1906 San Francisco earthquake," Bull. Seism. Soc. Am., 90, 1349-1351. pdf
  91. Wald, D., V. Quitoriano, T. Heaton, and H. Kanamori, 1999, Relationships between peak ground acceleration, peak ground velocity, and Modified Mercalli Intensity in California, Earthquake Spectra, 15, 557-564. pdf
  92. Wald, D., V. Quitoriano, T. Heaton, H. Kanamori, C. Scrivner, and B. Worden, 1999, TriNet “ShakeMaps”: rapid generation of peak ground motion and intensity maps for earthquakes in southern California, Earthquake Spectra, 15, 537-555. pdf
  93. Aagaard, B., J. Hall, and T. Heaton, 2000, Sensitivity study of near-source ground motion, Proceedings of the Twelfth World Conference in Earthquake Engineering, Aukland, New Zealand.
  94. Aagaard, B., J. Hall, and T. Heaton, 2000, Simulation of near-source ground motions with dynamic failure, Proceedings of the ASCE Structures Congress, Philadelphia, Pa.
  95. Kanamori, H., and T. Heaton, 2000, Microscopic and macroscopic physics of earthquakes, contained in Geocomplexity and the Physics of Earthquakes, Editors J. Rundle, D. Turcotte, and W. Klein, Geophysical Monograph 20, Published by the American Geophysical Union, D.C., 127-141.pdf
  96. Kanamori, H. and T. Heaton, 2000, Microscopic and macroscopic physics of earthquakes, Geophysical Monograph-American Geophysical Union, 120, 147-164.
  97. Behr, J.,Bryant, B., Given, D., Gross, K., Hafner, K., Hardebeck, J., Hauksson, E., Heaton, T., Hough, S., Hudnut, K., Hutton, K., Jones, L., Kanamori, H., Kendrick, K., King, N., Maechling, P., Meltzner, A., Ponti, D., Rockwell, T., Shakal, A., Simons, M., Stark, K,. Wald, D., Wald, L., and L. Zhu (2000). Preliminary Report on the 16 October 1999 M 7.1 Hector Mine, California, Earthquake. Seismological Research Letters, 71 (1). pp. 11-23. ISSN 0895-0695. pdf
  98. Aagaard, B., J. Hall, and T. Heaton, 2001, “Characterization of Near-source Ground Motions with Earthquake Simulations,” Earthquake Spectra, 17, 177-207. pdf
  99. Aagaard, B., T. Heaton, and J. Hall, 2001, “Dynamic earthquake ruptures in the presence of lithostatic normal stresses, implications for friction models and heat production,” Bulletin of the Seismological Society of America, 91, 1765-1796. pdf
  100. Hauksson, E., Small, P., Hafner, K., Busby, R., Clayton, R., Goltz, J., Heaton, T., Hutton, K., Kanamori, H., Polet, J., Given, D., Jones, L. and D. Wald, 2001, Southern California Seismic Network: Caltech/USGS Element of TriNet 1997-2001, Seism. Res. Let.,Volume 72, Number 6, 690-704, doi:10.1785/gssrl.72.6.690. pdf
  101. Clinton, J, and T. Heaton, 2002, “Potential advantages of a strong-motion velocity meter as opposed to a strong motion accelerometer,” Seismological Research Letters, 73, 332-342. pdf
  102. Aagaard, B., and T. Heaton, 2004, “Effect of fault dip and slip rate on near-source ground motions: why rupture directivity was minimal in the 1999 Chi-Chi, Taiwan earthquake”, Bull. Seism. Soc. Am., 94 (1), 155-170. pdf
  103. Aagaard, B., and T. Heaton, 2004, “Near-source ground motions from simulations of sustained intersonic and supersonic fault ruptures”, Bull. Seism. Soc. Am., 94, 2064-2078. pdf
  104. Bradford, S.C., J. Clinton, J Favela, and T. Heaton, 2004, Results of Millikan Library Forced Vibration Testing, Earthquake Eng. Res. Laboratory Report No. 2004-03, 39 p. pdf
  105. Smith, D., and B. Aagaard, and T. Heaton, 2005, “Teleseismic body waves from dynamically rupturing shallow thrust faults: are they opaque for surface reflected phases?”, Bull. Seism. Soc. Am., 95, 800-817. pdf
  106. Liu-Zeng, J., T. Heaton, and C. DiCaprio, 2005, “The effect of slip variability on earthquake slip-length scaling,” Geophys. J. Intl., 162 (3), 841-849. pdf
  107. Bradford, S., J. Clinton and T. Heaton, 2005, Variations in the Natural Frequencies of Millikan Library Caused by Weather and Small Earthquakes. Structures Congress 2005: pp. 1-11.doi: 10.1061/40753 (171) 90.
  108. Clinton, J., S.C. Bradford, T. Heaton, and J. Favela, 2006, “The observed wander of the natural frequencies in a structure,” Bull. Seism. Soc. Am, 96, 237-257. pdf
  109. Kohler, M, T. Heaton, R. Govindan, P. Davis, and D. Estrin, 2006, Using embedded wired and wireless seismic networks in the moment-resisting steel frame Factor building for damage identification, Proceedings of the 4th China-Japan-US conference on Structural Control and Monitoring. pdf
  110. Bradford, S.C., J. Yang, and T. Heaton, 2006, Variation in the dynamic properties of structures: the Wigner-Ville Distribution, Proceedings of the 8th U.S. National Conference on Earthquake Engineering, April 18-22, 2006, San Francisco, California, USA, Paper 1439.pdf
  111. Heaton. T., J. Yang, and J. Hall, 2006, Simulated performance of steel moment-resisting frame buildings in the 2003 Tokachi-Oki earthquake, Bull. Earthq. Res. Inst., Univ. Tokyo, 81, 325-329. pdf
  112. Cua, G., and Heaton, T, 2007, The Virtual Seismologist (VS) method: a Bayesian approach to earthquake early warning, in Seismic early warning, editors: P. Gasparini, G. Manfredi, J. Zschau, Springer Heidelberg, 97-132. pdf
  113. Kohler, M. D., T. Heaton, and C. Bradford, 2007, Propagating waves in the steel, moment-frame Factor building recorded during earthquakes, Bull. Seis. Soc. Am.,97, 1334-1345. pdf.
  114. Yamada, M., T. Heaton, and J. Beck, 2007, Early warning systems for large earthquakes: classification of near-source and far-source stations by using Bayesian model selection, Proceedings of the 10th International Conference on Applications of Statistics and Probability in Civil Engineering, Tokyo, Japan.
  115. Yamada, M., T. Heaton, and J. Beck, 2007, Real-time estimation of fault rupture extent using near-source versus far-source classification, Bulletin of the Seismological Society of America, 97 (6), 1890-1910. pdf.
  116. Heaton, T., 2007, Will performance based earthquake engineering break the power law?, Seism. Res. Lett., Vol. 78, No.2, 183-185. pdf
  117. Kohler, M., and T. Heaton, 2007 The UCLA Factor Building Seismic Array, IRIS newsletter, Issue 1, 5-7. pdf
  118. Olsen, A., B. Aagaard, and T. Heaton, 2008, Long-period building response to earthquakes in the San Francisco Bay area, Bull. Seism. Soc. Am., vol. 98, 1047-1065. pdf
  119. Aagaard, B., and T. Heaton, 2008, Constraining fault constitutive behavior with slip heterogeneity, J. Geophys. Res.,V. 113, B04301, doi:10.1029/2006JB004793 pdf.
  120. Yamada, M., and T. Heaton, 2008, Real-Time Estimation of Fault Rupture Extent Using Envelopes of Acceleration, Bull. Seism. Soc. Am., Vol. 98, No. 2, pp. 607–619. pdf.
  121. Böse, M, E. Hauksson, K. Solanki, H. Kanamori, and T.H. Heaton, 2008, Real-Time Testing of the On-site Warning Algorithm in Southern California and Its Performance During the July 29 2008 Mw5.4 Chino Hills Earthquake, Geophysical Research Letters, v. 36, (5), doi:10.1029/2008GL036366. pdf
  122. Yamada, M., J. Mori, and T. Heaton, 2008, The slapdown phase in high acceleration records of large earthquakes, Seismological Research Letters; 80 (4), 559 - 564. pdf
  123. Böse, M., E. Hauksson, K. Solanki, H. Kanamori, Y.-M. Wu, and T. H. Heaton, 2009, A New Trigger Criterion for Improved Real-Time Performance of On-site Earthquake Early Warning in Southern California, Bull. Seism. Soc. Am, 99: 897 - 905. pdf
  124. Yamada, M., A. Olsen, and T. Heaton, 2009, Statistical features of short- and long-period near-source ground motions, Bull. Seism. Soc. Am., 99: 3264 - 3274. pdf
  125. Cua, G., M. Fischer, T. Heaton, S. Wiemer, 2009, Real-time performance of the Virtual Seismologist earthquake early warning algorithm in southern California, Seismological Research Letters, September/October 2009; 80: 740 - 747. pdf
  126. Kohler, M., T, Heaton, V. Heckman, 2009, A Time‐Reversed Reciprocal Method for Detecting High‐Frequency Events in Civil Structures with Accelerometer Arrays, Proceedings of the 5th International Workshop on Advanced Smart Materials and Smart Structures Technology, Boston, MA, July 30‐31. pdf
  127. Cua, G. and T. Heaton, 2009, Characterizing average properties of southern California ground motion amplitudes and envelopes, Caltech Earthquake Engineering Laboratory Res. Report 2009-5, pdf
  128. Böse, M, and T. Heaton, 2010, Probabilistic Prediction of Rupture Length, Slip and Seismic Ground Motions for an Ongoing Rupture - Implications for Early Warning for Large Earthquakes, Geophysical J. Intl., V. 183, 1014 - 1030, DOI: 10.1111/j.1365-246X.2010.04774. pdf
  129. Heckman, V., M. Kohler and T. Heaton, 2010, Detecting Failure Events in Buildings: A Numerical and Experimental Analysis, XI World conference on Earthquake Engineering, Toronto, Canada. pdf
  130. Smith, D.E., and T. Heaton, 2010, Models of stochastic, spatially varying stress in the crust compatible with focal mechanism data, and how stress inversions can be biased toward the stress rate Bull. Seismological Soc. Am., V 101, 1396-1421, DOI: 10.1785/0120100058. pdf
  131. Hammond, W., B. Brooks, R. Burgmann, T. Heaton, M. Jackson, A. Lawry and S. Anandakrishnan, 2010, The scientific value of high-rate, low latency GPS data, white paper. pdf
  132. Yamada M., A. Olsen and T. Heaton, 2011, Reply to "Comment on 'Statistical Features of Short-Period and Long-Period Near-Source Ground Motions'" by R. Paolucci, C. Cauzzi, E. Faccioli, M. Stupazzini, and M. Villani, Bull. Seism. Soc. Am., 101, 919-924, DOI: 10.1785/0120100210. pdf
  133. Heckman, V., M. Kohler, and T. Heaton, 2011, A Method to Detect Structural Damage Using High‐Frequency Seismograms, 8th IWSHM Conference Proceedings, Stanford, CA, September 13 ‐15. pdf
  134. Cheng, M.H., V. Heckman, and T. Heaton, 2011, Mystery Revealed on Natural Frequency Change of a Structure during Rainstorms, 8th IWSHM Conference Proceedings, Stanford, CA, September 13‐15.
  135. Heckman, V., M Kohler, and T. Heaton, 2011, A Damage Detection Method for Instrumented Civil Structures Using Prerecorded Green’s Functions and Cross‐Correlation, 6th ANCRiSST, Dalian, China, July 25‐26.pdf
  136. Heckman, V., M. Kohler, and T. Heaton, 2011, A Method to Detect Structural Damage Using High‐Frequency Seismograms, 8CUEE Conference Proceedings, Tokyo, Japan, March 7‐8. pdf
  137. Clayton, R., T. Heaton, M. Chandy, A. Krause, M. Kohler, J. Bunn, R. Guy, M. Olson, M. Faulkner, M-H. Cheng, L. Strand, R. Chandy, D. Obenshain, A. Liu, and M. Aivazis, 2011, Community Seismic Network, Annals of Geophysics, 54, 6, 2011; doi: 10.4401/ag-5269. pdf
  138. Faulkner, M.,M. Olson, R. Chandy, J. Krause, K. M. Chandy, and A. Krause, 2011, The Next Big One: Detecting Earthquakes and Other Rare Events from Community-based Sensors Proceedings of the 10th ACM/IEEE International Conference on Information Processing in Sensor Networks. ACM. pdf
  139. Hammond, W., Brooks, B., Bürgmann,R., Heaton, T., Jackson, M., Lowry, A., and S. Anandakrishnan, 2011, Scientific Value of Real-Time Global Positioning System Data, Eos, Transactions American Geophysical Union, V. 92, Issue 15, 125-126, DOI: 10.1029/2011EO150001
  140. Böse, M., T. Heaton and E. Hauksson, 2012, Real-Time Finite Fault Rupture Detector (FinDer) for Large Earthquakes Using Image Rupture Techniques, 2012, Geophys. J. Int. 191 (2), 803–812 doi: 10.1111/j.1365-246X.2012.05657.x.pdf
  141. Böse, M., T.H. Heaton, and E. Hauksson, 2012: Earthquake Early Warning Using Data from Single Broadband or Strong-motion Sensor, Bull. Seism. Soc. Am., v. 102 (2), pp. 738- 750, April 2012, doi: 10.1785/0120110152. pdf
  142. Elbanna, A., and T. Heaton, 2012, A New Paradigm for Simulating Pulse-Like Ruptures: The Pulse Energy Equation, Geophys. J. Intl., 189, 1797–1806 doi: 10.1111/j.1365-246X.2012.05464.x. pdf
  143. Song, S., and T. Heaton, 2012, Predicting collapse of steel and reinforced-concrete frame buildings in different types of ground motions, 15th World Conference on Earthquake Engineering, Lisbon, Portugal. pdf
  144. Song, S., and T. Heaton, 2012, Prediction of Collapse from PGV and PGD, 15th World Conference on Earthquake Engineering, Lisbon, Portugal. pdf
  145. Cheng, M.H., T. Heaton, and R. Graves, 2012, Seismic Intensity Estimation of Tall Buildings in Earthquake Early Warning System, The 15th World Conference on Earthquake Engineering, 24-28 September 2012, Lisbon, Portugal. pdf
  146. Clayton, R.W., T. Heaton, M. Chandy, A. Krause, M. Kohler, J. Bunn and R. Guy, 2012, Community seismic network, Annals of Geophysics 54 (6).
  147. Faulkner, M., R. Clayton, T. Heaton, K. M. Chandy, M. Kohler, J. Bunn, R. Guy, A. Liu, M. Olson, M. H. Cheng, A. Krause, 2013, Community sense and response systems: your phone as quake detector, Communications of the Association for Computing Machinery (CACM), 57, 66-75.(pdf)
  148. Bӧse, M., Allen, R., Brown, H., Cua, G., Fischer, M., Hauksson, E., Heaton, T., Hellweg, M., Liukis, M., Neuhauser, D., Maechling, P. & CISN EEW Group, 2013: CISN ShakeAlert: An Earthquake Early Warning Demonstration System for California, in: F. Wenzel and J. Zschau(eds.) Early Warning for Geological Disasters - Scientific Methods and Current Practice; ISBN: 978-3-642-12232-3, Springer Berlin Heidelberg New York. pdf
  149. Kohler, M. D., T. H. Heaton, M. H. Cheng, 2013, The Community Seismic Network and Quake-Catcher Network: enabling structural health monitoring through instrumentation by community participants, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2013, edited by J. P. Lynch, C-B. Yun, K-W. Wang, Proc. of SPIE Vol. 8692, 86923X. pdf
  150. Krishnan, S., S. Pellegrino, and T. Heaton, 2013,   Deployable Structural Units and Systems, U.S. Patent No. 8,869,460.
  151. Olsen, A., T. Heaton, and J. Hall, 2013, Characterizing Ground Motions that Collapse Steel, Moment-Resisting Frames or Make Them Unrepairable, Earthquake Spectra, in press. pdf
  152. Wu, S, J. Beck, and T. Heaton, 2013, ePAD: Earthquake Probability-Based Automated Decision-Making Framework for Earthquake Early Warning, Computer-Aided Civil & Infrastructure Engineering, v.28 (10), 737-752.
  153. Cheng, M.H., and T. H. Heaton, 2013, Simulating building motions using the ratios of its natural frequencies and a Timoshenko beam model, Earthquake Spectra, in press.
  154. Cheng, M.H., S. Wu, T. Heaton, and J. Beck, 2013, Engineering Application in Buildings for Earthquake Early Warning System, submitted to Engineering Structures.
  155. Cheng, M.H., T. Heaton, and M. Kohler, 2013, Interpretation of Millikan Library's vibrating modes using a magneto coil to measure phase shifts, manuscript.
  156. Kohler, M. D., T. H. Heaton, M. H. Cheng, The Community Seismic Network and Quake-Catcher Network: enabling structural health monitoring through instrumentation by community participants, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, 2013, edited by J. P. Lynch, C-B. Yun, K-W. Wang, Proc. of SPIE Vol. 8692, 86923X, 2013.pdf
  157. Lawrence, J., E. Cochran, A. Chung, A. Kaiser, C. Christensen, R.Allen, J. Baker, B. Fry, T. Heaton, D. Kilb, M. Kohler, M.Taufer, 2014, Rapid Earthquake Characterization Using MEMS Accelerometers and Volunteer Hosts Following the Mw7.2 Darfield, New Zealand Earthquake, Bull. Seism. Soc. Am., 104 (1), 184-192.
  158. S. Wu, M.Cheng, J. Beck and T. Heaton, 2014, Uncertainty Analysis of Decision Making for Early Warning Application in Elevator Control, Tenth U.S. National Conference on Earthquake Engineering Frontiers of Earthquake Engineering, July 21-25, Anchorage, Alaska.
  159. Heaton, T., 2014, Northridge Twenty Years After, Seism. Res. Lett.,v. 85 no. 1 p. 1-4 . doi:10.1785/0220130194 pdf
  160. Faulkner, M., R. Clayton, T. Heaton, K.M. Chandy, M. Kohler, J. Bunn, and R.Guy, 2014, Community sense and response system: your phone as a quake detector, Communications of the ACM, v.57 (7), 66-75.
  161. Given, D., E. Cochran, T. Heaton, E. Hauksson, R. Allen, P. Hellweg, J. Vidale and P. Bodin, 2014, Technical Implementation Plan for the ShakeAlert Production System—An Earthquake Early Warning System for the West Coast of the United States, Open File Report 2014-1097. pdf
  162. Kohler, M. D., T. H. Heaton, M. H. Cheng, and P. Singh, Structural health monitoring through dense instrumentation by community participants: the Community Seismic Network and Quake-Catcher Network, 2014, 10th U.S. National Conference on Earthquake Engineering (NC10EE), Anchorage, Alaska, July 21-25. pdf
  163. Faulkner, M., R. Clayton, T. Heaton, K. M. Chandy, M. Kohler, J. Bunn, R. Guy, A. Liu, M. Olson, M. H. Cheng, A. Krause, 2014, Community sense and response systems: your phone as quake detector, Communications of the Association for Computing Machinery (CACM), 57, 66-75.pdf
  164. Cheng, M., S. Wu, T. Heaton and J. Beck, 2014, Earthquake early warning application to buildings, Engineering structures, v. 60, 155-164. pdf
  165. Cheng, M. and T. Heaton, 2015, Simulating building motions using ratios of the building's natural frequencies and Timoshenko Beam Model, Earthquake Spectra, v.31 (1), 403-420.
  166. Böse, M., and T. Heaton, 2015, Finite-Fault Rupture Detector (FinDer): Going Real-Time in Californian ShakeAlert Warning System, Seism. Res. Lett., in press.
  167. Kohler, M.D., A. Massari, T. Heaton, H. Kanamori, E. Hauksson, R. Guy, R. Clayton, J. Bunn, K. M. Chandy, 2015, Downtown Los Angeles 52-story High-Rise and Free-Field Response to an Oil Refinery Explosion, Eq Spectra, submitted.
  168. Meier, M. A., J. Clinton, and T. Heaton, 2015, The Gutenberg Algorithm: Evolutionary Bayesian Magnitude Estimates for Earthquake Early Warning with a Filter Bank, Bull. Seism. Soc. Am, in press
  169. Clayton, R. W., T. Heaton, M. Kohler, M. Chandy, R. Guy, and J. Bunn, 2015, Community Seismic Network: a dense array to sense earthquake strong motions, Seis. Res. Lett., in press.(pdf)
  170. Cheng, M. H., M. D. Kohler, and T. H. Heaton, 2015, Prediction of wave propagation in buildings using data from a single seismometer, Bull. Seis. Soc. Am., 105, 107-119, doi: 10.1785/0120140037, (pdf)
  171. Minson, S. E., B. Brooks, C. Glennie, J. Murray, J. Langbein, S. Owen, T. Heaton, R. Iannucci, and D. Hauser, 2015, Crowd Sourced Earthquake Early Warning, Science Advances. pdf
  172. Mendoza, C., S. Hartzell, T. Heaton, 2015, Finite-Fault Modeling of the Earthquake Source using Teleseismic Body Waves: A User’s Guide pd
  173. Meier, M. A., J. Clinton, and T. Heaton, 2015, The Gutenberg Algorithm: Evolutionary Bayesian Magnitude Estimates for Earthquake Early Warning with a Filter Bank, Bull. Seism. Soc. Am, in press
  174. Minson, S. E., B. Brooks, C. Glennie, J. Murray, J. Langbein, S. Owen, T. Heaton, R. Iannucci, and D. Hauser, 2015, Crowd Sourced Earthquake Early Warning, Science Advances. pdf
  175. Mendoza, C., S. Hartzell, T. Heaton, 2015, Finite-Fault Modeling of the Earthquake Source using Teleseismic Body Waves: A User’s Guide pdf
  176. Minson, S., Böse, M, Heaton, T., Hauksson, E., Murray, J, Langbein, J., Smith, D., and C. Felizardo, 2015, Joint Seismic-Geodetic Real-Time Models for Earthquake Early Warning, manuscript.
  177. Meier, M. A., Clinton, J., and T. Heaton. 2015, Earthquake rupture from up close: Near-source records of small and large earthquakes reveal universal rupture initiation statistics, accelerating rupture fronts and a scaling break at M~4, manuscript.
  178. Elbanna, A. E., and T. Heaton, 2015, Size Dependence of the Strength of a System with Velocity Weakening Friction, manuscript.
  179. Elbanna, A.E., and T. Heaton, 2015, Evolution of Stress Heterogeneity and Slip Complexity in systems with multiscale fractures using a discrete dynamical model, manuscript.
  180. Taghavi-Larigani, S., and T. Heaton, 2015, Feasility of using remotely-recorded optical videos and images to study deformations and structural health of buildings, dams, and any other structures and objects, Earthquake Engineering Research Laboratory Report, manuscript.
  181. Janover, C., Heaton, T., and J. Hall, 2015, Steel Converter and Caltech Virtual Shaker: Rapid Nonlinear Cloud-Based Structural Model Conversion and Analysis, Earthquake Engineering Researcl Laboratory Report, manuscript.

Heaton, T., A. Elbanna, B. Aagaard, and D. Smith, 2013, Implications of Strong-Rate-Weakening Friction for the Length-Scale Dependence of the Strength of the Crust; Why Earthquakes Are so Gentle, IASPEI, Gothenburg, Sweden pdf

Heaton, T., A. Olsen, M. Yamada, B. Aagaard, 2013, Statistical Characteristics of Earthquake Ground Motion; Has PBEE Broken the Power Law?, presentation in Kyoto Japan School of Architecture. pdf

Heaton, T., Boese, M., Hauksson, E., Allen, G., Cua, G., and M. Yamada, 2012, Earthquake Alerting in California, presented at ETH. pdf

Heaton, T., Clayton, R., Chandy, K.M., Kohler, M., Cheng, M.H., Cochrane, E., Lawrence, J., 2012, Community Seismic Network, presented at ETH. pdf

Heaton, T., M. Kohler. V. Heckman. M.H. Cheng, C. Bradford, B. Aagaard, J. Clinton, J. Favela, 2012, Using Seismometers to Detect Damage in Buildings. pdf

Heaton, T. and Jing Yang, 2009, Seismological Society of America Annual Meeting, Simulated Deformations of Seattle High-Rise Buildings from a Hypothetical Giant Cascadian Earthquake. pdf

Heaton, T.H., A. Elbanna, and J. Marsden, 2008 Fall AGU, Size dependence of stress in materials with self-organized critical prestress. pdf

Heaton, T., A. Olsen, J. Yang, M. Yamada, 2008 World Conference on Earthquake Engineering, Bejing, Simulations of Flexible Buildings in Large Earthquakes ppt

Heaton, T., G. Cua, M. Yamada, M. Böse, 2008, NRC Committee on Seismology and Geodynamics, Creating the Virtual Seismologist for seismic early warning. ppt