Publications

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The influence of noise in strong-motion records is most problematic at low and high frequencies where the signal to noise ratio is commonly low compared to that in the mid-spectrum. The impact of low-frequency noise (5 Hz) on computed pseudo-absolute response spectral accelerations (PSAs). In contrast to the case of low-frequency noise our analysis shows that filtering to remove high...

The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Bartlett Springs Fault Zone, California. The location and recency of the mapped traces is primarily based on geomorphic expression of the fault as interpreted from large-scale aerial photography. In a few places, evidence of fault creep and offset Holocene strata in...

A series of earthquakes hit the New Madrid seismic zone of southeastern Missouri, northeastern Arkansas, and adjacent parts of Tennessee and Kentucky, in December 1811 to February 1812. Three earthquakes had a magnitude of 7.0 or greater. The first earthquake occurred December 16, 1811, at 2:15 a.m.; the second 9 a.m. on January 23, 1812; and the third on February 7, 1812, at 3:45 a.m...

[1] The postseismic stress accumulation τ(t) over the interval 0.004 to 880 days following the 2004 Parkfield earthquake (M6) can be inferred from GPS measurements of postseismic deformation. The stress relaxation τ(t) − τ′lt, where τ′l is the interseismic loading rate and t is the time after the earthquake, plotted as a function of the number of M > 1.5 aftershocks Na(t) that have...

The spatiotemporal patterns of seismicity beneath Kilauea's south flank give insight to the structure and geometry of the decollement on which large, tsunamigenic earthquakes have occurred, and its relation to slow slip events (SSEs), which have been observed every 1 to 2 years since 1997. In order to record earthquakes triggered by a SSE that was predicted to occur in March 2007, a...

Ground deformation was monitored at earth fissures in areas of land subsidence induced by groundwater extraction in the southwestern United States. The ground deformation is consistent with the mechanism that fissures are caused by horizontal strains generated by bending of overburden in response to localized differential compaction. Subsidence profiles indicated that localized...

This publication is an update of an earlier report, U.S. Geological Survey (USGS) Geologic Investigation I-2812 by Wheeler and others (2003), titled ?Earthquakes in the Central United States-1699-2002.? Like the original poster, the center of the updated poster is a map showing the pattern of earthquake locations in the most seismically active part of the central United States. Arrayed...

We use newspaper accounts from the United States and Canada to assign modified Mercalli intensity (MMI) at 90 towns for the May 16, 1909 Northern Plains earthquake. Our MMI assignments generally are consistent with those plotted on Nuttli's (1976) isoseiemal map. The earthquake was felt over more than 1,500,000 km2 in the states of Minnesota, Montana, North Dakota, South Dakota, and...

I test a “clock-advance” model that implies triggered tremor is ambient tremor that occurs at a sped-up rate as a result of loading from passing seismic waves. This proposed model predicts that triggering probability is proportional to the product of the ambient tremor rate and a function describing the efficacy of the triggering wave to initiate a tremor event. Using data mostly from...

PAGER (Prompt Assessment of Global Earthquakes for Response) is an automated system that produces content concerning the impact of significant earthquakes around the world, informing emergency responders, government and aid agencies, and the media of the scope of the potential disaster. PAGER rapidly assesses earthquake impacts by comparing the population exposed to each level of shaking...

Nine hundred twenty seven seismic cone penetration tests (CPT) in a variety of geologic deposits and geographic locations were conducted by the U.S. Geological Survey (USGS) primarily between 1998 and 2008 for the purpose of collecting penetration test data to evaluate the liquefaction potential of different types of surficial geologic deposits (table 1). The evaluation is described in...