Probabilistic Fault Displacement Hazards for the Southern San Andreas Fault Using Scenarios and Empirical Slips

2011 ◽  
Vol 27 (2) ◽  
pp. 293-313 ◽  
Author(s):  
Rui Chen ◽  
Mark D. Petersen
Keyword(s):  
San Andreas Fault ◽  
Probabilistic Method ◽  
Hazard Mapping ◽  
Regression Equations ◽  
Earthquake Rupture ◽  
Hazard Maps ◽  
Mapping Accuracy ◽  
San Andreas ◽  
Rupture Model ◽  
Fault Displacement

We apply a probabilistic method to develop fault displacement hazard maps and profiles for the southern San Andreas Fault. Two slip models are applied: (1) scenario slip, defined by the ShakeOut rupture model, and (2) empirical slip, calculated using regression equations relating global slip to earthquake magnitude and distance along the fault. The hazard is assessed using a range of magnitudes defined by the Uniform California Earthquake Rupture Forecast and the ShakeOut. For hazard mapping we develop a methodology to partition displacement among multiple fault branches based on geological observations. Estimated displacement hazard extends a few kilometers wide in areas of multiple mapped fault branches and poor mapping accuracy. Scenario and empirical displacement hazard differs by a factor of two or three, particularly along the southernmost section of the San Andreas Fault. We recommend the empirical slip model with site-specific geological data to constrain uncertainties for engineering applications.

scholarly journals Displacement on the San Andreas fault subsequent to the 1966 Parkfield earthquake

1968 ◽  
Vol 58 (6) ◽  
pp. 1955-1973
Author(s):  
Stewart W. Smith ◽  
Max Wyss
Keyword(s):  
Shear Stress ◽  
Ground Motion ◽  
San Andreas Fault ◽  
High Rate ◽  
Aftershock Activity ◽  
Fault Surface ◽  
San Andreas ◽  
Parkfield Earthquake ◽  
Fault Displacement ◽  
Displacement Measurements

ABSTRACT Immediately following the 1966 Parkfield earthquake a continuing program of fault displacement measurements was undertaken, and several types of instruments were installed in the fault zone to monitor ground motion. In the year subsequent to the earthquake a maximum of at least 20 cm of displacement occurred on a 30 km section of the San Andreas fault, which far exceeded the surficial displacement at the time of the earthquake. The rate of displacement decreased logarithmically during this period in a manner similar to that of the decrease in aftershock activity. After the initial high rate of activity it could be seen that most of the displacement was occurring in 4–6 day epochs of rapid creep following local aftershocks. The variation of fault displacement along the surface trace was measured and shown to be consistent with a vertidal fault surface 44 km long and 14 km deep, along which a shear stress of 2.4 bars was relieved.

Active displacement on the Calaveras fault zone at Hollister, California

1971 ◽  
Vol 61 (2) ◽  
pp. 399-416
Author(s):  
Thomas H. Rogers ◽  
Robert D. Nason
Keyword(s):  
San Francisco ◽  
Fault Zone ◽  
Active Fault ◽  
San Andreas Fault ◽  
Fault System ◽  
Fault Creep ◽  
San Andreas ◽  
San Andreas Fault System ◽  
Fault Trace ◽  
Fault Displacement

abstract The Calaveras fault zone, which is a major branch of the San Andreas fault system in northern California, passes through the City of Hollister 160 km (100 miles) southeast of San Francisco. Active fault displacement (fault creep slippage) has occurred in and near Hollister along a fault trace within the Calaveras fault zone. Various man-made structures crossing the fault trace have been deformed and gradually offset in a right-lateral sense. The amount of offset varies directly with age of the structure. The maximum offset is 33 cm (13 in) of a sidewalk constructed in the period 1909 to 1914. Offsets on dated structures indicate displacement rates of approximately 2 mm/yr (0.08 in/yr) from 1909 to 1925 and 6 mm/yr (0.24 in/yr) from 1925 to 1967. Data obtained from periodic measurement of specially designed survey lines and instruments have indicated a displacement rate of 9 mm/yr (0.4 in/yr) since May 1967. Displacements of the survey lines are not associated with local earthquake events. Rates of active fault displacement vary with time and position along the Calaveras and San Andreas fault zones in the Hollister area. The pattern of this variation suggests that active displacement on the San Andreas fault zone may be transferring northeastward to the Calaveras fault zone.

More Fault Connectivity Is Needed in Seismic Hazard Analysis

2020 ◽  
Author(s):  
Morgan T. Page
Keyword(s):  
San Andreas Fault ◽  
Hazard Analysis ◽  
Length Distribution ◽  
Fault System ◽  
Earthquake Rupture ◽  
Present Evidence ◽  
The Third ◽  
Rupture Length ◽  
San Andreas ◽  
Improve Model

ABSTRACT Did the third Uniform California Earthquake Rupture Forecast (UCERF3) go overboard with multifault ruptures? Schwartz (2018) argues that there are too many long ruptures in the model. Here, I address his concern and show that the UCERF3 rupture-length distribution matches empirical data. I also present evidence that, if anything, the UCERF3 model could be improved by adding more connectivity to the fault system. Adding more connectivity would improve model misfits with data, particularly with paleoseismic data on the southern San Andreas fault; make the model less characteristic on the faults; potentially improve aftershock forecasts; and reduce model sensitivity to inadequacies and unknowns in the modeled fault system.

Estimating Surface Faulting Impacts from the ShakeOut Scenario Earthquake

2011 ◽  
Vol 27 (2) ◽  
pp. 315-330 ◽  
Author(s):  
Jerome A. Treiman ◽  
Daniel J. Ponti
Keyword(s):  
San Andreas Fault ◽  
Slip Distribution ◽  
Surface Rupture ◽  
Scenario Earthquake ◽  
Earthquake Scenario ◽  
San Andreas ◽  
Variable Nature ◽  
Rupture Model ◽  
Large Earthquakes

An earthquake scenario, based on a kinematic rupture model, has been prepared for a Mw 7.8 earthquake on the southern San Andreas Fault. The rupture distribution, in the context of other historic large earthquakes, is judged reasonable for the purposes of this scenario. This model is used as the basis for generating a surface rupture map and for assessing potential direct impacts on lifelines and other infrastructure. Modeling the surface rupture involves identifying fault traces on which to place the rupture, assigning slip values to the fault traces, and characterizing the specific displacements that would occur to each lifeline impacted by the rupture. Different approaches were required to address variable slip distribution in response to a variety of fault patterns. Our results, involving judgment and experience, represent one plausible outcome and are not predictive because of the variable nature of surface rupture.

Sign in / Sign up

Export Citation Format

Share Document