scholarly journals Short-term variations in slip rate and size of prehistoric earthquakes during the past 2000 years on the northern San Jacinto fault zone, a major plate-boundary structure in southern California

Lithosphere ◽  
2015 ◽  
Vol 7 (3) ◽  
pp. 211-234 ◽  
Author(s):  
Nathan W. Onderdonk ◽  
Sally F. McGill ◽  
Thomas K. Rockwell
Keyword(s):  
Fault Zone ◽  
Plate Boundary ◽  
Slip Rate ◽  
Boundary Structure ◽  
Short Term ◽  
San Jacinto Fault ◽  
The Past ◽  
San Jacinto Fault Zone ◽  
Past 2000 Years ◽  
Prehistoric Earthquakes

scholarly journals Latest Quaternary slip rates of the San Bernardino strand of the San Andreas fault, southern California, from Cajon Creek to Badger Canyon

Geosphere ◽  
2021 ◽  
Author(s):  
Sally F. McGill ◽  
Lewis A. Owen ◽  
Ray J. Weldon ◽  
Katherine J. Kendrick ◽  
Reed J. Burgette
Keyword(s):  
Confidence Interval ◽  
San Andreas Fault ◽  
Slip Rate ◽  
Alluvial Fan ◽  
Slip Rates ◽  
San Jacinto Fault ◽  
The Past ◽  
San Andreas ◽  
San Jacinto Fault Zone ◽  
San Bernardino

Four new latest Pleistocene slip rates from two sites along the northwestern half of the San Bernardino strand of the San Andreas fault suggest the slip rate decreases southeastward as slip transfers from the Mojave section of the San Andreas fault onto the northern San Jacinto fault zone. At Badger Canyon, offsets coupled with radiocarbon and optically stimulated luminescence (OSL) ages provide three independent slip rates (with 95% confidence intervals): (1) the apex of the oldest dated alluvial fan (ca. 30–28 ka) is right-laterally offset ~300–400 m yielding a slip rate of 13.5 +2.2/−2.5 mm/yr; (2) a terrace riser incised into the northwestern side of this alluvial fan is offset ~280–290 m and was abandoned ca. 23 ka, yielding a slip rate of 11.9 +0.9/−1.2 mm/yr; and (3) a younger alluvial fan (13–15 ka) has been offset 120–200 m from the same source canyon, yielding a slip rate of 11.8 +4.2/−3.5 mm/yr. These rates are all consistent and result in a preferred, time-averaged rate for the past ~28 k.y. of 12.8 +5.3/−4.7 mm/yr (95% confidence interval), with an 84% confidence interval of 10–16 mm/yr. At Matthews Ranch, in Pitman Canyon, ~13 km northwest of Badger Canyon, a landslide offset ~650 m with a 10Be age of ca. 47 ka yields a slip rate of 14.5 +9.9/−6.2 mm/yr (95% confidence interval). All of these slip rates for the San Bernardino strand are significantly slower than a previously published rate of 24.5 ± 3.5 mm/yr at the southern end of the Mojave section of the San Andreas fault (Weldon and Sieh, 1985), suggesting that ~12 mm/yr of slip transfers from the Mojave section of the San Andreas fault to the northern San Jacinto fault zone (and other faults) between Lone Pine Canyon and Badger Canyon, with most (if not all) of this slip transfer happening near Cajon Creek. This has been a consistent behavior of the fault for at least the past ~47 k.y.

Evidence for Seven Surface Ruptures in the Past 1600 Years on the Claremont Fault at Mystic Lake, Northern San Jacinto Fault Zone, California

2013 ◽  
Vol 103 (1) ◽  
pp. 519-541 ◽  
Author(s):  
Nathan W. Onderdonk ◽  
Thomas K. Rockwell ◽  
Sally F. McGill ◽  
Gayatri I. Marliyani
Keyword(s):  
Fault Zone ◽  
San Jacinto Fault ◽  
The Past ◽  
San Jacinto Fault Zone ◽  
Surface Ruptures

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.

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