A slow earthquake sequence on the San Andreas fault

Nature ◽  
1996 ◽  
Vol 383 (6595) ◽  
pp. 65-68 ◽  
Author(s):  
Alan T. Linde ◽  
Michael T. Gladwin ◽  
Malcolm J. S. Johnston ◽  
Ross L. Gwyther ◽  
Roger G. Bilham
Keyword(s):  
San Andreas Fault ◽  
Earthquake Sequence ◽  
Slow Earthquake ◽  
San Andreas

The July 2019 Ridgecrest, California, Earthquake Sequence Recorded by Creepmeters: Negligible Epicentral Afterslip and Prolonged Triggered Slip at Teleseismic Distances

2020 ◽  
Vol 91 (2A) ◽  
pp. 707-720 ◽  
Author(s):  
Roger Bilham ◽  
Bryan Castillo
Keyword(s):  
Surface Waves ◽  
Travel Time ◽  
San Andreas Fault ◽  
Surface Strain ◽  
Earthquake Sequence ◽  
Fault Creep ◽  
San Andreas ◽  
Garlock Fault ◽  
Growing Body ◽  
Epicentral Region

Abstract We report sequential triggered slip at 271–384 km distances on the San Andreas, Superstition Hills, and Imperial faults with an apparent travel-time speed of 2.2 ± 0.1  km/s, following the passage of surface waves from the 4 July 2019 (17:33:49 UTC) Mw 6.4 and 6 July 2019 (03:19:53 UTC) Mw 7.1 Ridgecrest earthquakes. Slip on remote faults was not triggered instantaneously but developed over several minutes, increasing in duration with distance. Maximum slip amplitudes varied from 10  μm to 5 mm within minutes of slip nucleation, but on the southernmost San Andreas fault slip continued for two months and was followed on 16 September 2019 by a swarm of microearthquakes (Mw≤3.8) near Bombay Beach. These observations add to a growing body of evidence that fault creep may result in delayed triggered seismicity. Displacements across surface faults in the southern epicentral region and on the Garlock fault in the months following the Ridgecrest earthquakes were negligible (<1.1  mm), and they are interpreted to characterize surface strain adjustments in the epicentral region, rather than to result from discrete slip on surface faults.

Bear Valley, California, earthquake sequence of February-March 1972

1975 ◽  
Vol 65 (2) ◽  
pp. 483-506 ◽  
Author(s):  
William L. Ellsworth
Keyword(s):  
San Andreas Fault ◽  
Aftershock Sequence ◽  
Earthquake Sequence ◽  
Fault System ◽  
The West ◽  
Rupture Surface ◽  
Source Areas ◽  
Focal Mechanism Solutions ◽  
The North ◽  
San Andreas

abstract The earthquake sequence of late February and March 1972 involved movement along the San Andreas fault and within the crustal wedge enclosed by the branching San Andreas and San Benito faults near Bear Valley, San Benito County, California. Activity was mainly confined to three distinct zones of strike-slip faulting: the short north-trending aftershock zone of the M 3.5 earthquake of February 22, 1972, the aftershock zone of the M 5.0 Bear Valley earthquake of February 24, 1972 located along the San Andreas fault, and the west-trending aftershock zone of the M 4.6 earthquake of February 27, 1972. The north-trending and west-trending zones lie between the two major splays of the branching fault system. Focal mechanism solutions from events in these zones are consistent with the transfer of horizontal, dextral displacement from the San Andreas fault to the San Benito, Paicines and Calaveras faults within the Bear Valley region. During the 18 months preceding the February 1972 sequence, the hypocentral regions of both the M 5.0 and M 4.6 shocks were characterized by concentrations of small earthquakes. Aftershock source areas of these two events progressively expanded during the course of the aftershock sequence. Estimates of the mainshock rupture surface for these events based on the distribution of aftershocks range over a factor of 4 owing to the irregular distribution of aftershocks and the rapid growth of the aftershock zone.

A note on relocating the 1963 Watsonville earthquakes

1982 ◽  
Vol 72 (4) ◽  
pp. 1309-1316
Author(s):  
David G. Evans ◽  
Thomas V. McEvilly
Keyword(s):  
San Andreas Fault ◽  
Velocity Model ◽  
Earthquake Sequence ◽  
Dense Network ◽  
Network Coverage ◽  
Site Specific ◽  
San Andreas ◽  
New Locations

abstract Events in the Watsonville earthquake sequence of August and September 1963 were found by Udias (1965) not to concentrate on the main San Andreas fault break. New locations are found using a more site-specific velocity model with carefully determined station adjustments. Resulting relocated hypocenters indicate that this sequence probably does not exhibit the anomalous spatial scatter found previously. The revised locations are found to be consistent with patterns of recent seismicity, based on dense network coverage, which show a tight coincidence with the San Andreas fault.

The San Andreas Fault

1993 ◽  
Author(s):  
Sandra S. Schulz ◽  
Robert E. Wallace
Keyword(s):  
San Andreas Fault ◽  
San Andreas
Sign in / Sign up

Export Citation Format

Share Document