Publications

Earthquake observations contributed by human observers provide an invaluable source of information to investigate both historical and modern earthquakes. Commonly, the observers whose eyewitness accounts are available to scientists are a self‐selected minority of those who experience a given earthquake. As such these may not be representative of the overall population that experienced...

The Hayward fault in California's San Francisco Bay area produces large earthquakes, with the last occurring in 1868. We examine how physics‐based dynamic rupture modeling can be used to numerically simulate large earthquakes on not only the Hayward fault, but also its connected companions to the north and south, the Rodgers Creek and Calaveras faults. Equipped with a wealth of images of...

The earthquake magnitude-frequency distribution is characterized by the b-value, which describes the relative frequency of large versus small earthquakes. It has been suggested that changes in b-value after an earthquake can be used to discriminate whether that earthquake is part of a foreshock sequence or a more typical mainshock-aftershock sequence, with a decrease in b-value heralding...

The 2020 Magna, Utah, earthquake produced observable crustal deformation over a ∼ 100 km2 area around the southeast margin of Great Salt Lake, but it did not produce any surface rupture. To obtain a detailed picture of the fault slip, we combine strong motion seismic waveforms with GPS static offsets and Interferometric Synthetic Aperture Radar (InSAR) observations to obtain kinematic and...

Seismic structural health monitoring (S2HM) has advanced significantly in the last three decades. However, currently there is no consensus on the need for real-time processing of data acquired during an earthquake. Numerous applications exist whereby S2HM-equipped systems record valuable seismic response data. A delayed use of the seismic data prohibits timely discovery of hidden damages...

Seismic response records were retrieved from the monitored 21-story (53.26-m-tall) typical Puerto Rican reinforced-concrete shear-wall dominated El Castillo Building in Mayaguez, 50 km from the mainshock epicenter of the January 7, 2020, Mw6.4 offshore Indios, Puerto Rico earthquake. The shear-wall-to-floor areas of the building are 0.97 and 3.49 in the longitudinal and transverse...

An earthquake and tsunamiI on November 28, 1945, sourced near the Makran coast of the Arabian Sea, disturbed port facilities and fishing villages to the east at Karachi Harbour. Seismic waves, some 300 kilometers from their Makran source, spilled mercury high in a lighthouse at Manora. One liter of the heavy, toxic liquid escaped from an annular trough in which one of the world’s...

Although small earthquakes are expected to produce weak shaking, ground motion is highly variable and there are outlier earthquakes that generate more shaking than expected—sometimes significantly more. We explore datasets of M 0.5–8.3 earthquakes to determine the relative impact of frequent, smaller-magnitude earthquakes that rarely produce strong ground motion, to rare, large...

The 73-story Wilshire Grand in downtown Los Angeles is the recently constructed tallest building in California. It is designed in conformance with performance-based design procedures. The lateral load resisting system of the building is designed with concrete core shear walls, three outriggers with buckling restrained braces (BRBs) located along the height and two three-story truss-belt...

Previous research has shown that online social networks can provide valuable insights regarding collective human responses to extreme natural events, such as earthquakes. Most previous studies focused on one large earthquake, while the 2019 Ridgecrest earthquakes involved two significant earthquakes occurring within a short period of time (a M6.4 foreshock on July 4 and a M7.1 mainshock...

No abstract available.

To what extent can the future evolution of an ongoing earthquake rupture be predicted? This question of fundamental scientific and practical importance has recently been addressed by studies of teleseismic source time functions (STFs) but reaching contrasting conclusions. One study concludes that the initial portion of STFs is the same regardless of magnitude. Another study concludes...