Peak horizontal acceleration and velocity from strong motion records including records from the 1979 Imperial Valley, California, earthquake

1981 ◽  
Author(s):  
W.B. Joyner ◽  
David M. Boore ◽  
R.L. Porcella
Keyword(s):  
Strong Motion ◽  
Imperial Valley ◽  
Strong Motion Records ◽  
Horizontal Acceleration ◽  
Peak Horizontal Acceleration

Peak horizontal acceleration and velocity from strong-motion records including records from the 1979 imperial valley, California, earthquake

1981 ◽  
Vol 71 (6) ◽  
pp. 2011-2038 ◽  
Author(s):  
William B. Joyner ◽  
David M. Boore
Keyword(s):  
Strong Motion ◽  
Fault Rupture ◽  
Imperial Valley ◽  
Attenuation Relations ◽  
Motion Data ◽  
Horizontal Acceleration ◽  
Anelastic Attenuation ◽  
Distance Dependence ◽  
Peak Horizontal Acceleration

Abstract We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceleration and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the data from the magnitude dependence. The resulting equations are log A = − 1.02 + 0.249 M − log r − 0.00255 r + 0.26 P r = ( d 2 + 7.3 2 ) 1 / 2 5.0 ≦ M ≦ 7.7 log V = − 0.67 + 0.489 M − log r − 0.00256 r + 0.17 S + 0.22 P r = ( d 2 + 4.0 2 ) 1 / 2 5.3 ≦ M ≦ 7.4 where A is peak horizontal acceleration in g, V is peak horizontal velocity in cm/ sec, M is moment magnitude, d is the closest distance to the surface projection of the fault rupture in km, S takes on the value of zero at rock sites and one at soil sites, and P is zero for 50 percentile values and one for 84 percentile values. We considered a magnitude-dependent shape, but we find no basis for it in the data; we have adopted the magnitude-independent shape because it requires fewer parameters.

scholarly journals Rupture process of the 1987 Superstition Hills earthquake from the inversion of strong-motion data

1990 ◽  
Vol 80 (5) ◽  
pp. 1079-1098 ◽  
Author(s):  
David J. Wald ◽  
Donald V. Helmberger ◽  
Stephen H. Hartzell
Keyword(s):  
Small Area ◽  
Strong Motion ◽  
Rupture Process ◽  
Imperial Valley ◽  
Strong Motion Records ◽  
Motion Data ◽  
Single Asperity ◽  
The Third ◽  
Rupture Model ◽  
Stress Drops

Abstract A pair of significant earthquakes occurred on conjugate faults in the western Imperial Valley involving the through-going Superstition Hills fault and the Elmore Ranch cross fault. The first event was located on the Elmore Ranch fault, Ms = 6.2, and the larger event on the Superstition Hills fault, Ms = 6.6. The latter event is seen as a doublet teleseismically with the amplitudes in the ratio of 1:2 and delayed by about 8 sec. This 8-sec delay is also seen in about a dozen strong-motion records. These strong-motion records are used in a constrained least-squares inversion scheme to determine the distribution of slip on a 2-D fault. Upon closer examination, the first of the doublets was found to be itself complex requiring two episodes of slip. Thus, the rupture model was allowed to have three separate subevents, treated as separate ruptures, with independent locations and start times. The best fits were obtained when all three events initiated at the northwestern end of the fault near the intersection of the cross-fault. Their respective delays are 2.1 and 8.6 sec relative to the first subevent, and their moments are 0.4, 0.9, and 3.5 × 1025 dyne-cm, which is about half of that seen teleseismically. This slip distribution suggests multi-rupturing of a single asperity with stress drops of 60, 200, and 15 bars, respectively. The first two subevents were confined to a small area around the epicenter while the third propagated 18 km southwestward, compatible with the teleseismic and afterslip observations.

Peak acceleration, velocity, and displacement from strong-motion records

1980 ◽  
Vol 70 (1) ◽  
pp. 305-321
Author(s):  
David M. Boore ◽  
William B. Joyner ◽  
Adolph A. Oliver ◽  
Robert A. Page
Keyword(s):  
Regression Analysis ◽  
Peak Velocity ◽  
Strong Motion ◽  
Western North America ◽  
Peak Acceleration ◽  
Motion Data ◽  
Horizontal Acceleration ◽  
Large Structures ◽  
San Fernando ◽  
Peak Horizontal Acceleration

abstract Strong-motion data from earthquakes of western North America are examined to provide the basis for estimating peak acceleration, velocity, and displacement as a function of distance for three magnitude classes, 5.0 to 5.7, 6.0 to 6.4, and 7.1 to 7.6. Analysis of a subset of the data from the San Fernando earthquake shows that small but statistically significant differences exist between peak values of horizontal acceleration, velocity, and displacement recorded on soil at the base of small structures and values recorded at the base of large structures. The peak acceleration tends to be less and the peak velocity and displacement to be greater at the base of large structures than at the base of small structures. In the distance range used in the regression analysis (15 to 100 km), the values of peak horizontal acceleration recorded at soil sites in the San Fernando earthquake are not significantly different from the values recorded at rock sites, but values of peak horizontal velocity and displacement are significantly greater at soil sites.

scholarly journals Effect of distance on local magnitudes found from strong-motion records

1983 ◽  
Vol 73 (1) ◽  
pp. 265-280
Author(s):  
Paul C. Jennings ◽  
Hiroo Kanamori
Keyword(s):  
Near Field ◽  
Strong Motion ◽  
Similar Data ◽  
Attenuation Curve ◽  
Imperial Valley ◽  
Strong Motion Records ◽  
Motion Data ◽  
San Fernando ◽  
Numerous Data ◽  
A Site

abstract Values of local magnitude ML, are calculated from 56 strong-motion accelerograms recorded in the Imperial Valley earthquake of 15 October 1979 according to procedures developed earlier (Kanamori and Jennings, 1978). These data, plus similar data from the San Fernando earthquake of 9 February 1971 and additional, less numerous data from several other California earthquakes, are used to investigate the use of different measures of distance in near-field determinations of ML: this investigation has relevance for similar uses of distances in determining seismic design criteria. In addition, the consistency of the values of ML found from the strong-motion data is examined from the viewpoint of assessing the need for any correction in the standard attenuation curve, −log10A0(Δ). It was found that the most consistent values of ML result when distance is measured to the closest point on the surface trace of the fault if a site lies within a circle with diameter equal to the extent of faulting and centered on the center of faulting (center of energy release). Outside this circle, the distance measured to the center of the circle is recommended. A consistent trend in the values of ML found from strong-motion records is seen in the data. The values start, at zero distance, at essentially the far-field value and then decrease to −1/4 unit at about 20 km. Then they rise to +1/4 unit at 50 to 60 km. A smooth revision to the standard attenuation curve is presented which removes this systematic trend.

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