Approximate location of fault traces and historic surface ruptures within the Hayward fault zone between San Pablo and Warm Springs, California

1965 ◽  
Author(s):  
Dorothy H. Radbruch-Hall
1966 ◽  
Vol 56 (2) ◽  
pp. 257-279 ◽  
Author(s):  
Lloyd S. Cluff ◽  
Karl V. Steinbrugge

abstract Right lateral slippage on the Hayward fault has faken place in the Irvington and Niles districts of Fremont since the well known 1868 Hayward earthquake which produced surface ruptures from San Leandro to Warm Springs. This post-1868 movement has been occurring without being identified with strong earthquakes. Structures and railroads crossing the Hayward fault in the area under study date back to 1866. Fault slippage can be observed at ten separate locations along the strike of the Hayward fault in the Irvington-Niles districts of Fremont, California. One location predates the 1868 earthquake. There is no evidence for parallel lines of fault slippage within the approximately 200-foot wide fault zone. The slippage appears to have occurred within a 10-foot wide band parallel to the strike of the fault. Structures and railroads built at different times during the past 100 years give a time-history of the slippage. The slippage, if any, between 1868 and 1909 is unknown. From 1909 until as late as 1949 or early 1950, there was no observed fault slippage. Approximately one-half foot of slippage occurred between about 1949 or early 1950 and about 1957, and no measurable slippage since 1957.


Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 451
Author(s):  
Nasim Mozafari ◽  
Çağlar Özkaymak ◽  
Dmitry Tikhomirov ◽  
Susan Ivy-Ochs ◽  
Vasily Alfimov ◽  
...  

This study reports on the cosmogenic 36Cl dating of two normal fault scarps in western Turkey, that of the Manastır and Mugırtepe faults, beyond existing historical records. These faults are elements of the western Manisa Fault Zone (MFZ) in the seismically active Gediz Graben. Our modeling revealed that the Manastır fault underwent at least two surface ruptures at 3.5 ± 0.9 ka and 2.0 ± 0.5 ka, with vertical displacements of 3.3 ± 0.5 m and 3.6 ± 0.5 m, respectively. An event at 6.5 ± 1.6 ka with a vertical displacement of 2.7 ± 0.4 m was reconstructed on the Mugırtepe fault. We attribute these earthquakes to the recurring MFZ ruptures, when also the investigated faults slipped. We calculated average slip rates of 1.9 and 0.3 mm yr−1 for the Manastır and Mugırtepe faults, respectively.


2018 ◽  
Vol 108 (2) ◽  
pp. 619-638 ◽  
Author(s):  
Lucille A. Piety ◽  
Joanna R. Redwine ◽  
Sarah A. Derouin ◽  
Carol S. Prentice ◽  
Keith I. Kelson ◽  
...  

Author(s):  
Rich W. Briggs ◽  
William J. Stephenson ◽  
John H. McBride ◽  
Jackson K. Odum ◽  
Nadine G. Reitman ◽  
...  
Keyword(s):  

2005 ◽  
Vol 21 (1_suppl) ◽  
pp. 113-123 ◽  
Author(s):  
Khaled Hessami ◽  
Hadi Tabassi ◽  
Koji Okumura ◽  
Mohammad R. Abbassi ◽  
Takashi Azuma

The Bam fault zone is a major active fault zone in southeastern Iran. Geomorphic evidence indicates that it has been responsible for repeated faulting events since the late Pleistocene. The 26 December 2003 Bam earthquake was associated with a 14 km fresh surface rupture trending north-south along the preexisting Bam fault zone. However, an en echelon rupture pattern trending N 15° E developed in the surface of alluvial deposits 5 km west of the Bam fault, in an area where no fault trace is visible in the geomorphology. The slip along the surface ruptures ranged between 0.5 and 20 cm. Rather than being a direct manifestation of the earthquake fault that does not surface, the fresh surface ruptures associated with the Bam earthquake are secondary structures such as synthetic (Reidel) shears and mole tracks, which indicate right-lateral motion along the Bam fault zone. This is compatible with both the focal mechanism solutions of the earthquake and fault displacements during the late Pleistocene. Fresh surface structures indicate areas of dispersed strain not recognized on SAR interferometry.


2019 ◽  
Vol 109 (5) ◽  
pp. 1907-1921
Author(s):  
Yong‐Gang Li ◽  
Rufus D. Catchings ◽  
Mark R. Goldman

Abstract We present evidence for multiple fault branches of the West Napa fault zone (WNFZ) based on fault‐zone trapped waves (FZTWs) generated by two explosions that were detonated within the main surface rupture zone produced by the 24 August 2014 Mw 6.0 South Napa earthquake. The FZTWs were recorded by a 15‐kilometer‐long dense (100 m spacing) linear seismic array consisting of 155 4.5‐hertz three‐component seismometers that were deployed across the surface ruptures and adjacent faults in Napa Valley in the summer of 2016. The two explosions were located ∼3.5  km north and ∼5  km south of the 2016 recording array. Prominent FZTWs, with large amplitudes and long wavetrains following the P and S waves, are observed on the seismograms. We analyzed FZTW waveforms in both time and frequency domains to characterize the branching structure of subsurface rupture zones along the WNFZ. The 2014 surface rupture zone was ∼12  km in length along the main trace of the WNFZ, which appears to form an ∼400–600‐meter‐wide low‐velocity waveguide to depths in excess of 5–7 km. Seismic velocities within the main rupture are reduced by 40%–50% relative to the surrounding‐rock velocities. Within 1.5 km of the main trace of the WNFZ, there are at least two subordinate fault traces that formed 3‐ to 6‐kilometer‐long surface breaks during the 2014 mainshock. Our modeling suggests that these subordinate fault traces are also low‐velocity waveguides that connect with the main rupture at depths of ∼2–3  km, forming a flower structure. FZTWs were also recorded at seismic stations across the Carneros fault (CF), which is ∼1  km west of the WNFZ; this suggests that the CF connects with the WNFZ at shallow depths, even though the CF did not experience surface rupture during the 2014 Mw 6.0 mainshock. 3D finite‐difference simulations of recorded FZTWs imply a branching structure along multiple fault strands associated with the WNFZ.


2019 ◽  
pp. 71-96
Author(s):  
E. V. Deev

The conducted paleoseismological and archaeoseismological studies reveal three zones of concentration of the ancient and historical earthquakes in Gorny Altai which are related to the Kurai Fault zone, Katun, and South Terekta faults. The surface ruptures are detected within the Kurai Fault zone, which were formed in the epicentral zones of the paleoearthquakes that occurred 6500, 5800, 3200, and 1300 years ago and had magnitudes Mw = 6.7–7.6. The recurrence period of the paleoearthquakes is 700 to 2600 years. The detected secondary seismogenic deformations indicate that an epicentral zone of the paleoearthquake with an age of less than 12.5 ka (Mw = 7.2–7.6, intensity I = 10–11), the traces of earthquakes and their clusters with M ≥ 5–5.5 and I ≥ 6–7, which occurred about 150 and 90 ka ago, in the intervals of 38–19 ka ago (with a recurrence period of about 2 ka), and 19–12.5 ka ago are related to the southern part of the Katun Fault. The earthquake of I ≥ 5–6 which damaged the constructions of the Chultukov Log 1 burial mound in the period from IV century B.C. to the beginning of I century A.D. is associated with the northern part of the Katun Fault. In the zone of the South Terekhta Fault, the seismogenic displacements that occurred in VII–VIII centuries A.D. (Mw = 7.4–7.7, I = 9–11) and about 16 ka ago (M ≥ 7, I = 9–10) are revealed. The latter triggered the formation of a landslide-dammed lake which was destroyed by the earthquake about 6 ka ago (M ≥ 7, I = 9–10). Secondary paleoseismic deformations of the ancient earthquakes (M ≥ 5–5.5, I ≥ 6–7) are recorded in the sediments of the Uimon Basin with an age of 100–90 ka and about 77 ka. These results should be taken into account in designing a gas pipeline in the People’s Republic of China, building infrastructure for tourism, and elaborating the seismic zoning maps for the territory of the Russian Federation.


Sign in / Sign up

Export Citation Format

Share Document