The proximity of several recent earthquakes to the Los Angeles sedimentary basin provides an opportunity to isolate the effects of the basin on wave propagation. The 4 October 1987 aftershock (ML = 5.3) of the Whittier Narrows sequence and the 28 June 1991 Sierra Madre mainshock (ML = 5.8) are on a similar azimuth to stations overlying the deepest part of the basin. A distinctive feature of rec...

Detailed seismic investigation of an unusually intense earthquake swarm which occurred in the northern Gulf of California during March 1969 has provided new information about seismic processes which occur on actively spreading oceanic ridges and has placed some constraints on the elastic wave velocities beneath them. Activity during this swarm was similar to that of a foreshock-mainshock-afters...

Seismicity quiescences are best observed during sequences with multiple mainshocks and often emerge some delay after an initial phase of aftershock triggering. The mechanisms controlling this poorly understood, due to a lack systematic precise estimation the duration triggering which is made complicated by rapidly changing magnitude completeness mainshock. Here, we analyze how such delayed quie...

We present evidence that at least two of the three 1811–1812 New Madrid, central United States, mainshocks and the 1886 Charleston, South Carolina, earthquake triggered earthquakes at regional distances. In addition to previously published evidence for triggered earthquakes in the northern Kentucky/southern Ohio region in 1812, we present evidence suggesting that triggered events might have occ...

Introduction: The 2015 M s 5.8 Alxa Left Banner earthquake (Alxa eathquake) struck a sparsely inhabited area of Inner Mongolia, northwestern China. However, as first > 5 event on the Ningxia–Inner Mongolia segment North–South seismic zone for 24 years, is considerable scientific interest. Methods: In this study, distribution sequence was redetermined via analysis data from permanent and ...

The Southern California Seismic Network (SCSN) has produced the SCSN earthquake catalog from 1932 to the present, a period of more than 77 yrs. This catalog consists of phase picks, hypocenters, and magnitudes. We present the history of the SCSN and the evolution of the catalog, to facilitate user understanding of its limitations and strengths. Hypocenters and magnitudes have improved in qualit...

The Southern California Seismic Network (SCSN) has produced the SCSN earthquake catalog from 1932 to the present, a period of more than 77 yrs. This catalog consists of phase picks, hypocenters, and magnitudes. We present the history of the SCSN and the evolution of the catalog, to facilitate user understanding of its limitations and strengths. Hypocenters and magnitudes have improved in qualit...

Swarms are bursts of earthquakes without an obvious mainshock. Some have been observed to be associated with transient aseismic fault slip, while others thought related fluids. However, the association is rarely quantitative due insufficient data quality. We use high-quality GPS/GNSS, InSAR, and relocated seismicity study a swarm >2,000 which occurred between 30 September 6 October 2020, near W...

Static stress transfer from major earthquakes is commonly invoked as the primary mechanism for triggering aftershocks, but evaluating this depends on aftershock rupture plane orientations and hypocenter locations, which are often subject to significant observational uncertainty. We evaluate static change an unusually large data set comprising hundreds thousands of aftershocks following 1997 Umb...