We examine 20-yr data sets of seismic activity from 10 volcanic areas in the western United States for annual periodic signals (seasonality), focusing on large calderas (Long Valley caldera and Yellowstone) and stratovolcanoes (Cascade Range). We apply several statistical methods to test for seasonality in the seismic catalogs. In 4 of the 10 regions, statistically significant seasonal modulati...

The extent to which ongoing seismicity in intraplate regions represents long-lived aftershock activity is unclear. We examined historical and instrumental seismicity in the New Madrid central U.S. region to determine whether present-day seismicity is composed predominantly of aftershocks of the 1811-1812 earthquake sequence. High aftershock productivity is required both to match the observation...

The 1999 Chi-Chi earthquake (MW=7.6; ML=7.3) ruptured in an area considered unusual in that, historically, large earthquakes have been unheard of and the background seismicity are low. A detailed investigation of the crustal characteristics based on seismicity, subsurface structures and GPS surveys shows that crustal strength in the low-seismicity block was most likely stronger than in the surr...

Earthquakes may be induced by a wide range of anthropogenic activities such as mining, fluid injection and extraction, and hydraulic fracturing. In recent years, the increased occurrence of induced seismicity and the impact of some of these earthquakes on the built environment have heightened both public concern and regulatory scrutiny, motivating the need for a framework for the management of ...

Most of the seismicity in the Los Angeles Basin (LA Basin) occurs at depth below the sediments and is caused by transpressional tectonics related to the big bend in the San Andreas fault. However, some of the seismicity could be associated with fluid extraction or injection in oil fields that have been in production for almost a century and cover ~ 17% of the basin. In a recent study, first the...

This paper summarizes the development of a Geographic Information System for managing and analyzing information on the effects of earthquakes in historical times of China. The extensive bibliography documenting the seismicity from B.C.3000 showed the need to proceed towards a type of data storage that would also allow management of the same data. Application of GIS techniques allowed us to inse...

This work focuses on the seismic response of a volcano to different magmatic processes with the aim of sheding light on their driving physics as tracked by seismicity. We study seismic time series recorded at basaltic volcanoes and identify generic seismicity patterns characteristic of (i) inter-eruptive, (ii) reservoir feeding, (iii) reservoir leak, and (iv) dyke injection phases of volcanic a...

Seismic hazard analyses are associated with large uncertainties when historical data are insufficient to define secular rates of seismicity. Such uncertainties may be decreased with geological data in areas where seismicity is shallow and produced by Quaternary faulting. To illustrate, we examine intraplate Japan. Large intraplate earthquakes in Japan characteristically produce surface ruptures...

[1] The relationship between small-magnitude seismicity and large-scale crustal faulting along the Hayward Fault, California, is investigated using a double-difference (DD) earthquake location algorithm. We used the DD method to determine high-resolution hypocenter locations of the seismicity that occurred between 1967 and 1998. The DD technique incorporates catalog travel time data and relativ...