Publications

The Canterbury Earthquake Sequence (CES) began with the Darfield earthquake on 4 September 2010. Continual large and small aftershocks since that time have meant communities have cycled through repeated periods of impact, response and recovery. Scientific communication about aftershocks during such a prolonged sequence has faced distinct challenges. We conducted research to better...

Reverse time migration is often used to interpret acoustic or three‐component seismic recordings by creating an image of subsurface seismic reflectors. Here I describe elastic reverse time migration imaging functions that are cast as waveform misfit sensitivity kernels of contrasts in material parameters across hypothetical seismic discontinuities, that is, specular reflectors. The...

We explore how accurate earthquake early warning (EEW) can be, given our limited ability to forecast expected shaking even if the earthquake source is known. Because of the strong variability of ground motion metrics, such as peak ground acceleration (PGA) and peak ground velocity (PGV), we find that correct alerts (i.e., alerts that accurately predict the observed ground motion above a

Estimates of background noise of Global Positioning System‐derived time series of positions for 740 sites in the western United States are examined. These data consist of daily epochs of three components of displacements that are at least 9.75 years long within the interval between 2000 and 2018. We find that these time series have significant temporal correlations that could be...

The potential for a major earthquake in the Shumagin seismic gap, and the tsunami it could generate, was reported in 1971. However, while potentially tsunamigenic splay faults in the adjacent Unimak and Semidi earthquake segments are known, such features along the Shumagin segment were undocumented until recently. To investigate margin structure and search for splay faults, we...

Hydraulic fracturing has been inferred to trigger the majority of injection‐induced seismicity in the Zhaotong and Changning shale gas field, Sichuan basin of China, in contrast to the Midwestern United States, where massive wastewater disposal has been the dominant triggering mechanism. More than 15,000 earthquakes, with magnitudes ranging up to Mw 4.7, were recorded by a temporary...

Introduction Dos Palmas Preserve is a Colorado Desert oasis and wetland in Riverside County, California, located near the base of the Orocopia Mountains and northeast of the Salton Sea. The original source of water for the oasis was artesian springs that developed at the base of the Orocopia Mountains, but more abundant water supplies were later provided to Dos Palmas Preserve when the...

Earthquakes in unusual locations have become an important topic of discussion in both North America and Europe, owing to the concern that industrial activity could cause damaging earthquakes. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids...

In this paper we summarize data, methods, and models developed for a probabilistic assessment of fault displacement hazards across the U.S. We compare earthquake displacement data and empirical fault displacement models that have been developed for normal faults, strike-slip faults, and reverse faults. In general, the data and models are similar near the center of the fault for the three...

The 2014 U.S. Geological Survey national seismic hazard model for the conterminous U.S. will be updated in 2018 and 2020 to coincide with the Building Seismic Safety Council’s Project 17 timeline for development of new building code design criteria. The two closely timed updates are planned to allow more time for the Provisions Update Committee to analyze the consequences of the hazard...

The beating phenomenon observed in recorded earthquake responses of a tall building in Japan and of two others buildings in the U.S. are examined in this paper. The objective of the paper is to discuss the significance of beating and to estimate what percentage of total shaking energy impacting a building is contributed by beating when it occurs. Beating is prominent in the prolonged...

We utilize a two-step process to validate 0-4 Hz ground motion simulations using the 1989 Loma Prieta earthquake. In the first step we run multiple realizations using the Graves and Pitarka hybrid method as implemented on the SCEC Broadband Simulation Platform and compare these with near-fault (R 40 km) recorded motions. A total of 648 rupture scenarios are examined and from these...