Creep on the Sargent Fault over the Past 50 Yr from Alignment Arrays with Implications for Slip Transfer between the Calaveras and San Andreas Faults, California

2021 ◽  
Author(s):  
Daniel D. Mongovin ◽  
Belle Philibosian
Keyword(s):  
Creep Rate ◽  
Stress And Strain ◽  
Strain Accumulation ◽  
Fault Creep ◽  
Central Section ◽  
The Past ◽  
San Andreas ◽  
Slip Transfer ◽  
Seismic Strain ◽  
Locked Fault

ABSTRACT The 55-km-long Sargent fault connects the creeping Calaveras fault with the locked San Andreas fault through the Santa Cruz Mountains west of Gilroy, California. The position of the Sargent fault between these two faults may have implications for slip transfer and strain accumulation between a creeping and locked fault. The detection and measurement of creep on the Sargent fault would indicate where interseismic strain is accumulating adjacent to these neighboring faults. In 1969, two alignment arrays separated by 3.7 km were installed across the central section of the Sargent fault to investigate potential creep. These arrays were measured in 1970 and 1975, and comparison of these measurements yielded a creep rate of 3.4 ± 0.6 mm/yr across two fault strands in the northern array; results from the southern array were never published. In 2019 and 2020, we resurveyed both arrays using a total station and analyzed the results to determine accumulated fault creep. Our results show that between 1970 and 2020, a period of 49.3 yr, the northern array was dextrally offset 164 ± 25 mm across the same two fault strands that were active in the 1970s, yielding an average creep rate of 3.3 ± 1.3 mm/yr. Thus, it appears that the 5 and 50 yr creep rates at this site are similar. The southern array, which may not span the entire fault zone, was dextrally offset 84 ± 13 mm across two fault strands between 1970 and 2019, yielding an average creep rate of 1.7 ± 0.8 mm/yr over 48.9 yr. These recent surveys document continued creep on the Sargent fault, which may reduce seismic strain accumulation and therefore seismic hazard. However, continued aseismic slip on this fault may result in the redistribution of stress and strain to adjacent faults and should be an area of continued study.

SLIP TRANSFER AND THE GROWTH OF THE INDIO AND EDOM HILLS, SOUTHERN SAN ANDREAS FAULT 

2016 ◽  
Author(s):  
Kate Scharer ◽  
◽  
Kim Blisniuk ◽  
Warren Sharp ◽  
Simon Marius Mudd
Keyword(s):  
San Andreas Fault ◽  
San Andreas ◽  
Slip Transfer

Strain Measurement by X-ray Diffraction Methods

1949 ◽  
Vol 1 (3) ◽  
pp. 211-224
Author(s):  
G. B. Greenough
Keyword(s):  
Strain Measurement ◽  
Plastic Anisotropy ◽  
Stress And Strain ◽  
Routine Method ◽  
X Ray Diffraction ◽  
Strain Measurements ◽  
X Ray ◽  
The Past ◽  
Polycrystalline Metals ◽  
The Individual

SummaryMany papers have been written on the measurement of strain by X-ray diffraction methods and on the interpretation of these strains in terms of stresses. Whereas, during the past few years, the experimental methods of determining the strains have. remained largely unchanged, research has shown that the older techniques for calculating stresses from strains are not always valid.In this paper an attempt is made to describe some of the principles of strain measurement by X-ray diffraction methods to those who are unfamiliar with the methods. The types of stress and strain systems which may exist in polycrystalline metals are then considered, particular attention being paid to the effect of the elastic and plastic anisotropy of the individual crystals. Some indication is given as to how the earlier methods of interpreting X-ray strain measurements should be modified, but no rigid routine method is proposed for use in a general case.

Creep on the San Andreas fault

1960 ◽  
Vol 50 (3) ◽  
pp. 389-415
Author(s):  
Karl V. Steinbrugge ◽  
Edwin G. Zacher ◽  
Don Tocher ◽  
C. A. Whitten ◽  
C. N. Claire
Keyword(s):  
Creep Rate ◽  
San Andreas Fault ◽  
Total Duration ◽  
Fault Line ◽  
Fault Movement ◽  
Central California ◽  
San Andreas ◽  
Different Types ◽  
Present Rate ◽  
Local Earthquake

ABSTRACT Progressive destruction of buildings and other works of man at the W. A. Taylor Winery near Hollister, California, indicates that one side of a segment of the San Andreas fault is creeping relative to the other. Three different types of measurements all yield an annual rate of creep of approximately one-half inch per year. Steinbrugge and Zacher: Measurements of the separations of pairs of reference marks adjacent to the line of creep have been repeated periodically since 1956, and damage to structures provides a good measure of the total creep since 1948. Reports of damage to older buildings on the same site suggest that the creep may have been going on at about the present rate for fifty or more years. Tocher: Creep recorders designed to measure continuously the differential lateral movement of adjacent sections of the concrete floor have been installed in the main winery building. The creep rate so determined has been about one-half inch per year (with right-lateral sense) for the past two years. Creep accumulates largely in spasms of rather short duration (on the order of a week) separated by intervals of weeks or months during which little or no creep takes place. Ninety-two per cent of the movement in a recent 371-day period accumulated in four spasms of total duration 34 days. Three of these spasms began at times when no local earthquakes were recorded on near-by seismographs; the fourth began with a sudden right-lateral fault movement of 3 mm. at the time of a sharp local earthquake (Richter magnitude 5.0) on January 20, 1960 (GCT). Whitten and Claire: Resurveys over monumented points established near the winery also yield a rate of slippage or creep along the fault line of one-half inch per year. A new method for analyzing the data obtained by retriangulating over monumented points at wide intervals (10 to 20 years) is presented and applied to two triangulation networks which cross the San Andreas fault in central California. Results from a net near Hollister show an average creep rate of about one-half inch per year; results from a net near Cholame (about 75 miles southeast of Hollister) show an average creep rate of about one-tenth inch per year. The results also give an angular value which represents the deformation in the crust adjacent to the fault line.

Observations of creep-related tilt, strain, and water-level changes on the central San Andreas fault

1977 ◽  
Vol 67 (3) ◽  
pp. 641-649 ◽  
Author(s):  
C. E. Mortensen ◽  
R. C. Lee ◽  
R. O. Burford
Keyword(s):  
Water Level ◽  
San Andreas Fault ◽  
Slip Surface ◽  
Lower Boundary ◽  
Water Level Fluctuations ◽  
Fault Creep ◽  
San Andreas ◽  
Strain Data ◽  
Data Source ◽  
Surface Creep

abstract Several simultaneous observations of surface fault creep, tilt, strain, and water-level fluctuations have been recorded along the San Andreas fault in the vicinity of the Almaden-Cienega Winery south of Hollister, California. Creep events recorded on the winery creepmeters on February 16, 1975, and by the winery and Harris Ranch creepmeters on September 17, 1975, were modeled as migrating dislocations with geometries chosen to give results that match the observed tilt and strain data. Source depths for the February 16th and September 17th creep events were found to be relatively shallow, the depth to the lower boundary of the slip surface being 0.4 and 2.0 km, respectively. In both cases slip was found to propagate from the northwest toward the southeast, which is consistent with changes in water level observed in a well near the winery. Since the installation of the tiltmeter and strainmeter 0.8 km northwest of the Cienega Winery, six tilt and strain signals with durations typical of creep events have been related to observed surface creep, while 11 such signals appear unrelated to recorded surface creep. The latter may result from surface creep of limited extent or creep at depth.

Women in the history of linguistics

2020 ◽  
pp. 1-30
Author(s):  
Wendy Ayres-Bennett ◽  
Helena Sanson
Keyword(s):  
Language Acquisition ◽  
Central Section ◽  
Future Directions ◽  
The Past ◽  
Early Stages ◽  
Challenges And Opportunities ◽  
History Of Linguistics ◽  
History Of ◽  
Role Of Women

This Introduction outlines the need for a ‘true history’ (Lerner 1976) of the role of women in the history of linguistics, which considers them on their own terms, and challenges categories and concepts devised for traditional male-dominated accounts. We start by considering what research has already been conducted in the field, before exploring some of the reasons for the relative dearth of studies. We outline some of the challenges and opportunities encountered by women who wished to study the nature of language and languages in the past. The geographical and chronological scope of this volume is then discussed. In a central section we examine some of the major recurring themes in the volume. These include attitudes towards women’s language, both positive and negative; women and language acquisition and teaching; and women as creators of new languages and scripts. We further explore women as authors, dedicatees, or intended readers of metalinguistic texts, as interpreters and translators, and as contributors to the linguistic documentation and maintenance. We consider how women supported male relatives and colleagues in their endeavours, sometimes in invisible ways, before reviewing the early stages of their entry into institutionalized contexts. The chapter concludes with a brief section on future directions for research.

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