Source parameters of small earthquakes recorded at 2.5 km depth, Cajon Pass, southern California: Implications for earthquake scaling

1993 ◽  
Vol 20 (14) ◽  
pp. 1511-1514 ◽  
Author(s):  
Rachel Abercrombie ◽  
Peter Leary
Keyword(s):  
Southern California ◽  
Source Parameters ◽  
Earthquake Scaling

Earthquake Source Parameters in Southwestern China and Their Rheological Implications

2020 ◽  
Vol 91 (2A) ◽  
pp. 936-947
Author(s):  
Qingdong Wang ◽  
Risheng Chu
Keyword(s):  
Southern California ◽  
Depth Distribution ◽  
Source Parameters ◽  
Focal Mechanisms ◽  
Yunnan Region ◽  
Brittle Ductile Transition ◽  
Earthquake Source Parameters ◽  
China Earthquake ◽  
International Seismological Centre ◽  
Minimum Moment

Abstract Earthquake depth distribution provides key information on rheological behavior of the crust, which usually shows a brittle–ductile transition at a depth of about 10 km. In this study, we use the generalized cut-and-paste method to obtain source parameters of 571 earthquakes in the Sichuan–Yunnan region of China between 2009 and 2017. We were able to successfully determine focal mechanisms, moment magnitudes, and centroid depths of 536 earthquakes with a minimum moment magnitude of 3.2. Our moment magnitudes and centroid depths are systematically smaller than the magnitudes (Ms and mb) and hypocenter depths from the China Earthquake Network Center and International Seismological Centre catalogs for M≥4.0 earthquakes. The earthquake depths in the Sichuan–Yunnan region are mostly in a 5–9 km range, with an average at 7.6 km. About 23% earthquakes have centroid depths <5  km and are concentrated in the southern Sichuan basin. Only very few earthquakes are deeper than 19 km. Compared with the earthquake depth distribution in southern California, the Sichuan–Yunnan region has many shallower earthquakes. The depth distribution suggests that the brittle–ductile transition in the Sichuan–Yunnan region is shallower than the transition beneath southern California, which is probably due to the existence of newborn faults in the Sichuan–Yunnan region.

scholarly journals Preliminary work on an early warning and rapid response program for moderate earthquakes

1995 ◽  
Vol 85 (4) ◽  
pp. 1257-1265
Author(s):  
Craig W. Scrivner ◽  
Donald V. Helmberger
Keyword(s):  
Ground Motion ◽  
Southern California ◽  
San Andreas Fault ◽  
Ground Motions ◽  
Source Parameters ◽  
Reverse Direction ◽  
Peak Displacement ◽  
San Andreas ◽  
Single Station ◽  
Sierra Madre

Abstract Warning of imminent ground shaking due to a large earthquake would be useful to a variety of agencies. This kind of ground-motion prediction is possible in southern California for events with magnitude less than 6, where path effects dominate. The 28 June 1991 Sierra Madre earthquake is presented as a test case for this concept. A single-station inversion of the record from the Pasadena station 20 km SW of the epicenter produces reasonable source parameters for the event. With these source parameters and a library of Green's functions calculated for an average southern California crustal model, ground motions can be predicted throughout the region. In particular, since the peak displacement for the Sierra Madre event occurs at Pasadena before ground motion begins at a station near the San Andreas Fault in San Bernardino, ground motions near the San Andreas Fault can be calculated before the seismic energy has propagated into the area. Considering this scenario in the reverse direction, records from a station near an earthquake on the San Andreas Fault could be used to predict ground motions in the metropolitan Los Angeles area. Broadband, high-dynamic-range seismic instruments produce high-quality records for events over a wide magnitude range. Thus, the development of a warning system can be approached in stages, starting with small events. With path effects determined by modeling moderate-size events, work can begin on developing distributed fault models to predict ground motions of great earthquakes.

Source parameters of southern California earthquakes

1973 ◽  
Vol 78 (35) ◽  
pp. 8547-8576 ◽  
Author(s):  
Wayne Thatcher ◽  
Thomas C. Hanks
Keyword(s):  
Southern California ◽  
Source Parameters

The Effects of Presentation on Noise and Dental Appliances on Speech

1981 ◽  
Vol 24 (1) ◽  
pp. 151-151
Author(s):  
Lillian Glass ◽  
Sharon R. Garber ◽  
T. Michael Speidel ◽  
Gerald M. Siegel ◽  
Edward Miller
Keyword(s):  
Southern California ◽  
University Of Southern California ◽  
University Of Minnesota ◽  
School Of Medicine ◽  
Southern California School ◽  
School Of Dentistry ◽  
The University

An omission in the Table of Contents, December JSHR, has occurred. Lillian Glass, Ph.D., at the University of Southern California School of Medicine and School of Dentistry, was a co-author of the article "The Effects of Presentation on Noise and Dental Appliances on Speech" along with Sharon R. Garber, T. Michael Speidel, Gerald M. Siegel, and Edward Miller of the University of Minnesota, Minneapolis.

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