scholarly journals U.S. Geological Survey strong-motion records from the Northern California (Loma Prieta) earthquake of October 17, 1989

1989 ◽  
Author(s):  
R.P. Maley ◽  
A.V. Acosta ◽  
F. Ellis ◽  
E.C. Etheredge ◽  
L.J. Foote ◽  
...  
Keyword(s):  
Strong Motion ◽  
Geological Survey ◽  
Northern California ◽  
Strong Motion Records ◽  
Loma Prieta Earthquake ◽  
Loma Prieta ◽  
October 17

Simulating strong motions of large earthquakes using recordings of small earthquakes: the Loma Prieta mainshock as a test case

1995 ◽  
Vol 85 (4) ◽  
pp. 1144-1160
Author(s):  
Arthur Frankel
Keyword(s):  
Stress Drop ◽  
Site Response ◽  
Strong Motion ◽  
Site Effect ◽  
Corner Frequency ◽  
Simple Method ◽  
Strong Motion Records ◽  
Loma Prieta Earthquake ◽  
Loma Prieta ◽  
Large Earthquakes

Abstract A simple method is developed for predicting ground motions for future large earthquakes for specific sites by summing and filtering recordings of adjacent small earthquakes. This method is tested by simulating strong-motion records for the Loma Prieta earthquake (M 7.0) using aftershocks (M 3.7 to 4.0) recorded at the same sites. I use an asperity rupture model where the rms stress drop averaged over the fault plane is constant with moment. The observed spectra indicate that stress drop remains constant from the M 3 aftershocks up to the M 7 mainshock, about six orders of magnitude in seismic moment. Each simulation sums the seismogram of one aftershock with time delays appropriate for propagating rupture and incorporates directivity and site response. The simulation scales the spectrum in accordance with a constant stress drop, ω−2 source model. In this procedure, the high-frequency energy of the aftershock sum above the corner frequency of the aftershock is not reduced when it is convolved with the mainshock slip velocity function, unlike most previous methods of summation. For most cases, the spectra (0.6 to 20 Hz), peak accelerations, and durations of the simulated mainshock records are in good agreement with the observed strong-motion records, even though only one aftershock waveform was used in each simulation. This agreement indicates that the response of these soil sites is essentially linear for accelerations up to about 0.3 g. The summed aftershock records display the same site-dependent values of fmax as the mainshock records, implying that fmax is a site effect rather than a property of the mainshock rupture process.

Strong-Motion Records at Army Hospitals in California from the Loma Prieta Earthquake of 17 October 1989

1990 ◽  
Author(s):  
Pamalee A. Brady ◽  
James B. Gambill ◽  
William J. Gordon ◽  
John R. Hayes ◽  
Jr
Keyword(s):  
Strong Motion ◽  
Strong Motion Records ◽  
Loma Prieta Earthquake ◽  
Army Hospitals ◽  
Loma Prieta

scholarly journals Performance assessment of damaged bridge bents after the Loma Prieta earthquake

1992 ◽  
Vol 25 (1) ◽  
pp. 44-51
Author(s):  
M. J. N. Priestley ◽  
F. Seible
Keyword(s):  
Department Of Transportation ◽  
California Department ◽  
Loma Prieta Earthquake ◽  
Assessment Design ◽  
Bridge Structures ◽  
Loma Prieta ◽  
Consistent Assessment ◽  
October 17 ◽  
Bridge Bents ◽  
Seismic Repair

Following the October 17, 1989 Loma Prieta Earthquake, a large number of damaged and undamaged structural concrete bridge structures had to be assessed and evaluated for seismic repair and retrofit. The lack of consistent assessment and evaluation models prompted the formulation of the outlined procedures in a first attempt to develop a comprehensive basis for the seismic assessment and retrofit of existing bridge structures. The presented principles are currently being developed at UCSD into consistent assessment design models in cooperation with the California Department of Transportation.

scholarly journals Rupture model of the 1989 Loma Prieta earthquake from the inversion of strong-motion and broadband teleseismic data

1991 ◽  
Vol 81 (5) ◽  
pp. 1540-1572 ◽  
Author(s):  
David J. Wald ◽  
Donald V. Helmberger ◽  
Thomas H. Heaton
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
High Gain ◽  
Temporal And Spatial Distribution ◽  
Origin Time ◽  
Loma Prieta Earthquake ◽  
Motion Data ◽  
Teleseismic Data ◽  
Loma Prieta

Abstract We have used 24 broadband teleseismic and 48 components of local strong-motion velocity records of the 1989 Loma Prieta earthquake in a formal inversion to determine the temporal and spatial distribution of slip. Separate inversions of the teleseismic data (periods of 3 to 30 sec) or strong-motion data (periods of 1 to 5 sec) result in similar models. The data require bilateral rupture with relatively little slip in the region directly updip from the hypocenter. Slip is concentrated in two patches: one centered 6 km northwest of the hypocenter at a depth of 12 km and with a maximum slip of 350 cm, and the other centered about 5 km southeast of the hypocenter at a depth of 16 km and with a maximum slip of 460 cm. The bilateral nature of the rupture results in large amplitude ground motions at sites located along the fault strike, both to the northwest and the southeast. However, the northwestern patch has a larger moment and overall stress drop and is, consequently, the source of the largest ground motion velocities, consistent with the observed recordings. This bilateral rupture also produces relatively modest ground motion amplitudes directly updip from the hypocenter, which is in agreement with the velocity ground motions observed at Corralitos. There is clear evidence of a foreshock (magnitude between 3.5 and 5.0) or a slow rupture nucleation about 2 sec before the main part of the rupture; the origin time implied by strong-motion trigger times is systematically 2 sec later than the time predicted from the high-gain regional network data. The seismic moment obtained from either of the separate data sets or both sets combined is about 3.0 × 1026 dyne-cm and the potency is 0.95 km3.

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