2019 IRIS/SSA Distinguished Lecturers

Dr. Susan Hough

Research Geophysicist
U.S. Geologic Survey Pasadena,
Pasadena, California

What Past Earthquakes Tell Us About Future Earthquake Hazard: Facts & Fake Facts

Curriculum Vitae

Susan Hough graduated from the University of California, Berkeley with a degree in geophysics in 1982 and received a PhD in Earth sciences from the University of California, San Diego in 1988. Since 1992 she has worked as a research geophysicist at the US Geological Survey in Pasadena. Her research interests include earthquake ground motions, induced earthquakes, historical earthquakes, and seismic hazard. She led deployments of portable seismometers following a number of damaging earthquakes, including the 1989 Loma Prieta, California, and 2010 Haiti earthquakes. She has co-authored over 120 articles, and was elected Fellow of the American Geophysical Union in 2009. She is now serving as President-Elect of the Seismological Society of America. In addition to technical articles, she has a long-standing interest in science communication, having authored five books on earthquake science for a non-specialist audience as well as numerous popular articles. She has further led USAID-supported capacity development projects in a number of countries including Nepal, Haiti, and Myanmar.

Seismologists spend their lives working to understand earthquakes, including earthquakes caused by human activities, so that we can understand and mitigate the hazard they pose. Fortunately for us all, large earthquakes do not strike frequently in any one place. Many of the most important past earthquakes occurred before the invention of modern seismometers. To understand these events, scientists draw on sleuthing skills to explore all available sources of data. In this talk, I describe some of the ingenious work that has been done to understand past earthquakes, and the lessons they can teach us about present-day earthquake hazard. I also discuss evidence that, while earthquakes induced by wastewater injection appeared to be a new phenomenon, there is evidence that humans caused earthquakes in a number of places, including Oklahoma and Texas, as far back as the early 20th century.

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Dr. Arthur Rodgers

Seismologist
Atmospheric, Earth & Energy Division,
Lawrence Livermore National Laboratory,
Livermore, California

Supercomputer Modeling of Earthquake Ground Motions 150 Years After the 1868 Hayward Fault Rupture

Curriculum Vitae

Arthur Rodgers joined Lawrence Livermore National Laboratory (LLNL) as a seismologist in 1997. He has worked on high-performance computing and computational seismology since 2004. This worked involved modeling of seismic waves from earthquakes and explosions. Dr. Rodgers has worked with teams on modeling earthquakes in the San Francisco Bay Area, as well as educational outreach with the California Academy of Sciences (2012), LLNL’s Science on Saturday (2015) and the American Museum of Natural History (2018). He obtained a B.S. in Physics from Northeastern University and a Ph.D. from the University of Colorado in 1993. He was a postdoctoral scholar at New Mexico State University (1994) and the University of California Santa Cruz (1994-1996). In 2010, he was a Fulbright Scholar to Grenoble France. He is currently a Visiting Researcher at Lawrence Berkeley National Laboratory and the University of California Berkeley Seismology Laboratory.

The last major earthquake on the Hayward Fault, with magnitude 6.5-7.0, occurred on October 21, 1868. This earthquake caused significant damage to structures for the few thousands of people living in the “East Bay” at that time. Geologic evidence strongly suggests major earthquakes on the Hayward Fault occur about every 140-160 years. 2018 marked the 150th anniversary of this event, and 2.5 million people live near the Hayward Fault today. Consequently, the Hayward Fault contributes significantly to seismic hazard and risk in the San Francisco Bay Area. This lecture will describe supercomputer modeling of earthquake ground motions with a focus on large Hayward Fault ruptures. Computer simulations of earthquakes can be performed to understand the expected level and character of shaking for possible future events. Advances in numerical methods and the ever growing power of parallel processing supercomputers enable ever more realistic modeling of earthquake shaking, including geology and topography. I’ll describe how computer simulations are enabled by world-class supercomputers and how these simulations are generating ever more realistic motions for hazard and risk studies.

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