Paleoseismic Investigations of the Walnut Site on the San Jacinto Fault

2008 ◽  
Author(s):  
T.E. Fumal ◽  
K.J. Kendrick
Keyword(s):  
San Jacinto Fault

scholarly journals Analysis of Seismic Signals Generated by Vehicle Traffic with Application to Derivation of Subsurface Q-Values

2021 ◽  
Author(s):  
Haoran Meng ◽  
Yehuda Ben-Zion ◽  
Christopher W. Johnson
Keyword(s):  
Surface Waves ◽  
Anthropogenic Sources ◽  
Correct Identification ◽  
Vehicle Traffic ◽  
Seismic Properties ◽  
Shallow Subsurface ◽  
San Jacinto Fault ◽  
San Jacinto Fault Zone ◽  
Estimate Frequency ◽  
Q Values

Abstract Correct identification and modeling of anthropogenic sources of ground motion are of considerable importance for many studies, including detection of small earthquakes and imaging seismic properties below the surface. To understand signals generated by common vehicle traffic, we use seismic data recorded by closely spaced geophones normal to roads at two sites on San Jacinto fault zone. To quantify the spatiotemporal and frequency variations of the recorded ground motions, we develop a simple analytical solution accounting for propagation and attenuation of surface waves. The model reproduces well-observed bell-shaped spectrograms of car signals recorded by geophones close to roads, and it can be used to estimate frequency-dependent Q-values of the subsurface materials. The data analysis indicates Q-values of 3–40, for frequencies up to 150 Hz for road-receiver paths at the two examined sites. The derived Q-values are consistent with attenuation factors of surface waves previously obtained with other methods. The analytical results and analysis procedure provide a highly efficient method for deriving Q-values of shallow subsurface materials.

scholarly journals Basic data features and results from a spatially dense seismic array on the San Jacinto fault zone

2015 ◽  
Vol 202 (1) ◽  
pp. 370-380 ◽  
Author(s):  
Yehuda Ben-Zion ◽  
Frank L. Vernon ◽  
Yaman Ozakin ◽  
Dimitri Zigone ◽  
Zachary E. Ross ◽  
...  
Keyword(s):  
Fault Zone ◽  
Seismic Array ◽  
Basic Data ◽  
San Jacinto Fault ◽  
San Jacinto Fault Zone ◽  
Dense Seismic Array

A re-examination of historic earthquakes in the San Jacinto fault zone, California

1991 ◽  
Vol 81 (6) ◽  
pp. 2289-2309
Author(s):  
Allison L. Bent ◽  
Donald V. Helmberger
Keyword(s):  
Fault Zone ◽  
Source Parameters ◽  
Travel Times ◽  
Considerable Uncertainty ◽  
San Jacinto Fault ◽  
San Jacinto Fault Zone ◽  
Moment Estimates ◽  
The Moment ◽  
Recent Earthquakes ◽  
Historic Earthquakes

Abstract The high level of seismic activity and the potential for large earthquakes in the San Jacinto fault zone, southern California, make it desirable to have accurate locations and source parameters for as many previous events as possible. Prior to the installation of a dense seismic network in this region, earthquakes were located using only a few stations with generally poor azimuthal coverage resulting in considerable uncertainty in the locations. We relocate and obtain moment estimates for historic (pre-WWSSN) earthquakes in the western Imperial Valley by comparing the waveforms and travel times with recent earthquakes in the region. All the events are in the ML 5.5 to 6.5 range. The historic earthquakes of interest occurred in 1937, 1942, and 1954. We use the 1968 Borrego Mountain, 1969 Coyote Mountain, and 1987 Elmore Ranch earthquakes as calibration events. We employ regional and teleseismic data from continuously operating stations, with Pasadena, DeBilt, Berkeley, Ottawa, and St. Louis recording most of the events. The waveforms imply that all the events are almost pure strike-slip events on vertical or near-vertical faults. Approximate values for the strikes were obtained and are within the range of observed strikes for well-studied earthquakes in this region. The earthquakes are relocated by comparing S-P and surface-wave - S travel times of historic events with the presumably well-located recent events. The relocations require only a small change in location for the 1954 event and a larger adjustment in the 1942 epicenter. It also appears that the 1969 earthquake may have been mislocated. The moment estimates are obtained by direct comparison of the maximum amplitudes. The moment estimates imply that the 1968 and not the 1942 earthquake is the largest to have occurred in the region this century. Previous magnitude estimates suggested the 1942 event was larger.

Structural Properties of the San Jacinto Fault Zone at Blackburn Saddle from Seismic Data of a Dense Linear Array

2018 ◽  
Vol 176 (3) ◽  
pp. 1169-1191 ◽  
Author(s):  
Pieter-Ewald Share ◽  
Amir A. Allam ◽  
Yehuda Ben-Zion ◽  
Fan-Chi Lin ◽  
Frank L. Vernon
Keyword(s):  
Structural Properties ◽  
Fault Zone ◽  
Seismic Data ◽  
Linear Array ◽  
San Jacinto Fault ◽  
San Jacinto Fault Zone
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