scholarly journals Short-period Spectral Level, Path and Site-amplification Derived from Strong Motion Records during the Normal-faulting Earthquakes in Hamadori, Fukushima Prefecture in 2011

2012 ◽  
Vol 12 (7) ◽  
pp. 7_1-7_18 ◽  
Author(s):  
Toshimi SATOH ◽  
Hideaki TSUTSUMI
Keyword(s):  
Strong Motion ◽  
Site Amplification ◽  
Normal Faulting ◽  
Strong Motion Records ◽  
Fukushima Prefecture ◽  
Short Period

scholarly journals Shake Map Methodology for Intermediate-Depth Vrancea (Romania) Earthquakes

2009 ◽  
Vol 25 (3) ◽  
pp. 497-514 ◽  
Author(s):  
Maren Böse ◽  
Vladimir Sokolov ◽  
Friedemann Wenzel
Keyword(s):  
Ground Motions ◽  
Strong Motion ◽  
Site Amplification ◽  
Attenuation Relations ◽  
Intermediate Depth ◽  
Amplification Factors ◽  
Strong Motion Records ◽  
Vrancea Earthquakes ◽  
Shake Map ◽  
Good Agreement

We establish and test a shake map methodology for intermediate-depth Vrancea earthquakes, based on seismological information gathered in Romania during recent years. We use region- (azimuth-) dependent attenuation relations derived from stochastic simulations of ground motions using spectral models of Vrancea earthquakes. Both region boundaries and Fourier amplification spectra for the characterization of seismic site effects are based on several hundred weak, moderate and strong-motion records and macroseismic intensity maps. We determine region-specific, magnitude- and distance-dependent amplification factors of peak values and instrumental intensity relative to rock. We interpolate recorded ground motions and ground motion estimates from the obtained amplification factors and attenuation relations for rock conditions. The resulting shake maps show a good agreement with macroseismic descriptions of moderate-sized and large Vrancea earthquakes, demonstrating the feasibility of a seismological approach to shake map generation. Unlike previous methodologies, this approach requires neither expensive assessments of geology-dependent site amplification factors, nor large numbers of strong-motion records. Our results are in good agreement with empirical topographic slope-site amplification relations, but give a better reflection of the abnormal attenuation of seismic waves in the Transylvanian region and the strong amplification in the Focsani basin.

High stress drops of short-period subevents from the 1968 Tokachi-Oki earthquake as observed on strong-motion records

1984 ◽  
Vol 74 (5) ◽  
pp. 1529-1544
Author(s):  
Jim Mori ◽  
Kunihiko Shimazaki
Keyword(s):  
Source Parameters ◽  
High Stress ◽  
Strong Motion ◽  
P Waves ◽  
Strong Motion Records ◽  
Source Dimensions ◽  
Short Period ◽  
High Dynamic ◽  
Stress Drops ◽  
Very High

Abstract Strong-motion records of the 1968 Tokachi-Oki earthquake were examined, and two very high stress drop subevents were identified. The first subevent had been previously located by Nagamune (1969), and the second subevent was located in this study using P waves recorded on short-period WWSSN records. Estimates of source parameters revealed small source dimensions (<1 per cent of the aftershock area) and very high dynamic and static stress drops in the kilobar range for both of the subevents. It is suggested that these subevents are important in driving the main rupture of this earthquake. The two subevents also produced the dominant accelerations on the strong-motion records, and it is shown that high-peak accelerations (150 to 200 cm/sec2) were recorded even at relatively large distances (100 to 200 km).

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