The Whittier Narrows, California Earthquake of October 1, 1987—CSMIP Strong Motion Data

1988 ◽  
Vol 4 (1) ◽  
pp. 75-100 ◽  
Author(s):  
A. Shakal ◽  
M. J. Huang ◽  
T. Q. Cao
Keyword(s):  
Los Angeles ◽  
Strong Motion ◽  
Suspension Bridge ◽  
State University ◽  
Peak Acceleration ◽  
Ground Response ◽  
Data Set ◽  
Strong Motion Records ◽  
Motion Data ◽  
Soft Story

The Whittier Narrows earthquake of October 1, 1987 generated the largest set of strong-motion records ever obtained from a single earthquake. The California Strong Motion Instrumentation Program (CSMIP) recovered 128 strong-motion records from 101 stations. Of these 101 stations, 63 are ground-response stations and 38 are extensively-instrumented structures. The structures include 27 buildings, eight dams, a suspension bridge, an airport tower, and a power plant. This paper summarizes that data set and highlights records of particular interest. The duration of strong shaking was approximately 3 to 4 seconds at most stations. The maximum peak acceleration values in the CSMIP data set are 0.62 g on the ground and 0.54 g in a structure. The largest acceleration (0.62 g) was recorded at a station near Tarzana, approximately 45 km from the epicenter. Other records of particular interest discussed here include the record from a soft-story building on the Los Angeles State University campus and the records from the Vincent Thomas suspension bridge near Long Beach. Digitization and processing of the accelerograms are underway, and accelerograms from 12 ground-response stations have been digitized as of this writing. The spectra show that the motion at the Tarzana station was dominated by 3 Hz energy. Spectra from other sites are relatively flat and do not show this spectral peak. The attenuation of peak acceleration with distance for this earthquake is compared with the relationship of Joyner and Boore (1981) derived from past earthquakes. On average, the peak acceleration data from this earthquake are higher than would be predicted by the Joyner-Boore model.

Magnitude-dependent variance of peak ground acceleration

1995 ◽  
Vol 85 (4) ◽  
pp. 1161-1176
Author(s):  
R. R. Youngs ◽  
N. Abrahamson ◽  
F. I. Makdisi ◽  
K. Sadigh
Keyword(s):  
Standard Error ◽  
Peak Ground Acceleration ◽  
Strong Motion ◽  
Earthquake Magnitude ◽  
Peak Acceleration ◽  
Ground Acceleration ◽  
Data Set ◽  
Motion Data ◽  
Time Period ◽  
Vertical Accelerations

Abstract We examine the variability of peak horizontal and vertical accelerations of the large California strong-motion data set for the time period 1957 to 1991 and find a statistically significant dependence of the standard error on earthquake magnitude. Specifically, the standard error decreases with increasing magnitude. The analysis was conducted using a rigorous methodology that examines both earthquake to earthquake (inter-event) variability and within earthquake (intra-event) variability. The magnitude dependence is stronger for inter-event variability than intra-event variability, and stronger for horizontal peak acceleration than for vertical peak acceleration. The data from the recent Landers, Big Bear, and Northridge earthquakes are consistent with these results.

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.

scholarly journals Seismological and Engineering Characteristics of Strong Motion Data from 24 and 26 September 2019 Marmara Sea Earthquakes

2021 ◽  
Author(s):  
Fatma Sevil Malcıoğlu ◽  
Hakan Süleyman ◽  
Eser Çaktı
Keyword(s):  
Ground Motion ◽  
Prediction Models ◽  
Strong Motion ◽  
P Wave ◽  
Corner Frequency ◽  
Marmara Region ◽  
Marmara Sea ◽  
S Wave ◽  
Data Set ◽  
Motion Data

Abstract An MW 4.5 earthquake took place on September 24, 2019 in the Marmara Sea. Two days after, on September 26, 2019, Marmara region was rattled by an MW5.7 earthquake. With the intention of compiling an ample strong ground motion data set of recordings, we have utilized the stations of Istanbul Earthquake Rapid Response and Early Warning System operated by the Department of Earthquake Engineering of Boğaziçi University and of the National Strong Motion Network operated by AFAD. All together 438 individual records are used to calculate the source parameters of events; namely, corner frequency, radius, rupture area, average source dislocation, source duration and stress drop. Some of these parameters are compared with empirical relationships and discussed extensively. Duration characteristics are analyzed in two steps; first, by making use of the time difference between P-wave and S-wave onsets and then, by considering S-wave durations and significant durations. It is observed that they yield similar trends with global models. PGA, PGV and SA values are compared with three commonly used ground motion prediction models. At distances closer than about 60 km observed intensity measures mostly conform with the GMPE predictions. Beyond 60 km their attenuation is clearly faster than those of GMPEs. Frequency-dependent Q models are developed for both events. Their consistency with existing regional models are confirmed.

Moment-magnitude relations based on strong-motion records in Greece

1999 ◽  
Vol 89 (2) ◽  
pp. 442-455 ◽  
Author(s):  
B. N. Margaris ◽  
C. B. Papazachos
Keyword(s):  
Strong Motion ◽  
Soil Classification ◽  
Moment Magnitude ◽  
Systematic Bias ◽  
Local Magnitude ◽  
Strong Motion Data ◽  
Strong Motion Records ◽  
Motion Data ◽  
Input Acceleration ◽  
The Difference

Abstract In this work, the variation of the local magnitude, MLSM, derived from strong-motion records at short distances is examined, in terms of moment magnitude, MW. Strong-motion data from Greek earthquakes are used to determine the strong-motion local magnitude, MLSM, by performing an integration of the equation of motion of the Wood-Anderson (WA) seismograph subjected to an input acceleration. The most reliable strong-motion data are utilized for earthquakes with seismic moments log M0 ≧ 22.0 dyne · cm and calculated local magnitudes, MLSM ≧ 3.7. The correlation between the seismic moments, log M0, and the calculated local magnitudes, MLSM, using strong-motion records is given by log M0 = 1.5*MLSM + 16.07, which is very similar to that proposed by Hanks and Kanamori (1979). Moreover, it is shown that MLSM is equal to moment magnitude, MW, for a large MLSM range (3.9 to 6.6). Comparison of the strong-motion local magnitude and the ML magnitude estimated in Greece (MLGR) and surrounding area shows a systematic bias of 0.4 to 0.5, similar to the difference that has been found between MW and MLGR for the same area. The contribution of the local site effects in the calculation of the local magnitude, MLSM, is also considered by taking into account two indices of soil classification, namely, rock and alluvium or the shear-wave velocity, v30s, of the first 30 m, based on NEHRP (1994) and UBC (1997). An increase of MLSM by 0.16 is observed for alluvium sites. Alternative relations showing the MLSM variation with, v30s are also presented. Finally, examination of the WA amplitude attenuation, −log A0, with distance shows that the Jennings and Kanamori (1983) relation for Δ < 100 km is appropriate for Greece. The same results confirm earlier suggestions that the 0.4 to 0.5 bias between MLGR and MW (also MLSM) should be attributed to a low static magnification (∼800) of the Athens WA instrument on which all other ML relations in Greece have been calibrated.

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.

Engineering Analysis of Ground Motion Records from the 2001 Mw 8.4 Southern Peru Earthquake

2010 ◽  
Vol 26 (2) ◽  
pp. 499-524 ◽  
Author(s):  
Adrian Rodriguez-Marek ◽  
James A. Bay ◽  
Kwangsoo Park ◽  
Gonzalo A. Montalva ◽  
Adel Cortez-Flores ◽  
...  
Keyword(s):  
Shear Wave ◽  
High Frequency ◽  
Ground Motions ◽  
Strong Motion ◽  
Frequency Content ◽  
Engineering Analysis ◽  
Data Set ◽  
Strong Motion Records ◽  
Southern Peru ◽  
High Frequency Content

The Mw 8.4 23 June 2001 Southern Peru earthquake generated intense ground motions in a large region encompassing southern Peru and northern Chile. The earthquake was recorded by seven strong motion stations with peak ground accelerations ranging from 0.04 g to 0.34 g for site-to-fault distances ranging from about 70 km to 220 km. At this time, there are no other strong motion records for an earthquake of this magnitude. Hence, the strong motion data set from this earthquake is unique and of particular interest to engineers dealing with seismic design in subduction regions. This paper presents an engineering analysis of the strong motion records. Shear-wave velocity profiles were measured using Spectral Analysis of Surface Waves methods at four stations. Measured shear-wave velocities are high, indicating that all sites classify as stiff soil sites (Site C) according to the International Building Code classification scheme. The strong motion set is characterized by strong high frequency content at large distances from the fault. Site response contributed at least in part to the observed high frequency content in the ground motions. In general, current attenuation relationships for spectral acceleration underpredicted the observed ground motions.

scholarly journals The 2003, Mw 7.2 Fiordland earthquake, and its near-source aftershock strong motion data

2004 ◽  
Vol 37 (3) ◽  
pp. 139-145
Author(s):  
P. McGinty
Keyword(s):  
New Zealand ◽  
Strong Motion ◽  
Data Set ◽  
Strong Motion Data ◽  
Preliminary Results ◽  
Motion Data ◽  
Magnitude Range ◽  
Source Data ◽  
Peak Ground Accelerations ◽  
Attenuation Models

The 2003 Fiordland earthquake was not only the best ever recorded subduction interface earthquake to occur in New Zealand, it also provided the opportunity to collect near-source strong-motion data produced by its aftershocks covering a wide magnitude range. Near source strong-motion data had been lacking in the New Zealand data set, on which current attenuation models are based. Here the author presents some preliminary results relating recorded peak ground accelerations in the near-source field to current attenuation models. The near-source data from the 2003 Fiordland earthquake sequence has shown that the observed data has a greater magnitude-dependence than that predicted by the current attenuation models. This new data will help to improve current models and will lead to a better understanding of the attenuation process associated with New Zealand subduction interface earthquakes.

The Whittier Narrows, California Earthquake of October 1, 1987—Early Results of Isoseismal Studies and Damage Surveys

1988 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
E. V. Leyendecker ◽  
L. M. Highland ◽  
M. Hopper ◽  
E. P. Arnold ◽  
P. Thenhaus ◽  
...  
Keyword(s):  
Los Angeles ◽  
Field Survey ◽  
Ground Motions ◽  
Geographical Area ◽  
Mail Survey ◽  
Strong Motion ◽  
Peak Acceleration ◽  
Early Results ◽  
Acceleration Data ◽  
Strong Ground

Preliminary isoseismals for Modified Mercalli intensities are presented for the Whittier Narrows Earthquake. Isoseismals for intensities VI and lower are based on responses to a mail survey. Intensity VII and larger are based on a field survey of damage described in this paper. The maximum observed intensity of VIII was confined to Whittier. The shapes of the intensity contours compare favorably with the distribution of average peak acceleration data from the strong motion array in the greater Los Angeles area. The damage assessments appeared consistent with earthquake magnitude. However, the accelerations were higher than expected for the magnitude. The building classification and survey strategies developed were tested and found usable and adequate for describing damage. With further refinement this system can be used to describe damage within a limited geographical area and in a format useful for correlations with strong ground motions and the Modified Mercalli Intensity scale.

scholarly journals ACCELEROMETRIC DATA AND WEB PORTAL FOR THE VERTICAL CORINTH GULF SOFT SOIL ARRAY (CORSSA)

2017 ◽  
Vol 50 (2) ◽  
pp. 1081
Author(s):  
I. Kassaras ◽  
Z. Roumelioti ◽  
O.-J. Ktenidou ◽  
K. Pitilakis ◽  
N. Voulgaris ◽  
...  
Keyword(s):  
Soft Soil ◽  
Strong Motion ◽  
Web Portal ◽  
Seismic Region ◽  
Data Set ◽  
Corinth Gulf ◽  
Motion Data ◽  
Linear Behaviour ◽  
Scientific Value ◽  
Gathering Data

Strong motion data recorded during the 15-year operation of the CORinth Gulf Soft Soil Array (CORSSA) in the highly seismic region of Aegion have been homogenized and organized in a MySQL database. In the present work we describe the contents of the database and the web portal through which these data are publicly accessible. CORSSA comprises one surface and four downhole 3-D broadband accelerometric stations. It was installed in 2002, in the framework of European project CORSEIS, aiming at gathering data for studying site effects, liquefaction, and non-linear behaviour of soils, as well as earthquake source properties. To date, the array has recorded 549 local and regional events with magnitudes ranging from 1.1 to 6.5. Although the vast majority of the recorded events caused weak ground motion at the CORSSA site, the scientific value of the data set pertains to the sparsity of this kind of infrastructure in most parts of the world.

Sign in / Sign up

Export Citation Format

Share Document