Response spectral attenuation relationships for Sumatran-subduction earthquakes and the seismic hazard implications to Singapore and Kuala Lumpur   总被引：1，自引：0，他引：1  

Kusnowidjaja Megawati  Tso-Chien Pan  Kazuki Koketsu 《Soil Dynamics and Earthquake Engineering》2005,25(1):11-25

Singapore and Kuala Lumpur, the capital of Malaysia, may well represent the classic examples of area with low seismic hazard but with high consequence. Both cities are located in a low-seismicity region of Southeast Asia, where active seismic sources are located more than 300 km away. Seismic designs have not been implemented in this seemingly low-hazard region though distant earthquakes in Sumatra had frequently shaken high-rise structures in the two cities. Several studies have been conducted to systematically assess the seismic hazards of Singapore and the Malay Peninsula. The present research particularly addresses issues in deriving a new set of attenuation relationships of peak ground acceleration (PGA), peak ground velocity (PGV) and response spectral acceleration (RSA) for the Sumatran-subduction earthquakes. To be relevant for the seismic hazard assessment of the remote metropolises, the derived attenuation relationships cover a long distance range from 150 to 1500 km. The attenuation relationships are derived using synthetic seismograms that account for source and path effects. The uncertainties in rupture parameters, such as stress drop, strike, dip and rake angles, have been defined according to the regional geological and tectonic settings as well as the ruptures of previous earthquakes. The seismic potential of the Sumatran subduction zone are high in the region from 2°N to 5°S as there has been no recurrence of great thrust events since 1861. A large event with M_w greater than 7.8 in this particular subduction zone may be capable of generating destructive ground motions in Singapore and Kuala Lumpur, even at a distance of 700 km.  相似文献   

Discussion of “An attenuation relationship based on Turkish strong motion data and iso-acceleration map of Turkey” by Ulusay et al., Eng. Geol., 74: 265–291 (2004)     

E. Kalkan  P. Gülkan 《Engineering Geology》2005,79(3-4):288-290

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Attenuation in Southeastern Carpathians area: Result of upper mantle inhomogeneity   总被引：1，自引：0，他引：1  

M. Popa  M. Radulian  B. Grecu  E. Popescu  A.O. Placinta 《Tectonophysics》2005,410(1-4):235-249

The systematic analysis of seismograms recorded on the Romanian territory using Vrancea intermediate-depth earthquakes shows a strong asymmetric pattern relative to the epicentral area: on one side, in the Transylvanian Basin and the Eastern Carpathians (approximately along the inner volcanic chain), the amplitudes are reduced by a factor of 20 on average and the high frequencies are attenuated, in contrast with the other side, in the foreland platform. This pattern is explained by a significant attenuation increase caused by a strong lateral variation of the structure in the upper mantle, immediately towards NW of the Vrancea seismic active volume. This region corresponds to the most recent volcanic activity in the Persani Mountains and with the low-velocity body adjacent toward NW to the high-velocity body subducted beneath Vrancea area as indicated by seismic tomography and heat flow results. The CALIXTO'99 tomography experiment, deployed for 6 months in 1999, provides the largest number of observations for Vrancea earthquakes ever recorded on the Romanian territory. We select data from 8 earthquakes generated in this time interval in the Vrancea nest, which were recorded with signal / noise ratio greater than 5 by at least 25 stations. All of them are small- to moderate-magnitude events (3.6 ≤ M_w ≤ 4.2). The attenuation is much more important in the high-frequency range (> 1 Hz), than at low frequencies. Since the large Vrancea earthquakes can radiate significant energy in the low-frequency range (< 1 Hz), our results show that the seismic hazard level is much more uniform all over the Romanian territory in the low-frequency range than in the high-frequency range.  相似文献   

Array measurements of S-wave velocities from ambient vibrations   总被引：3，自引：1，他引：3  

Fortunat Kind  Donat Fäh  Domenico Giardini 《Geophysical Journal International》2005,160(1):114-126

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Constraints on the location and mechanism of the 1511 Western-Slovenia earthquake from active tectonics and modeling of macroseismic data   总被引：4，自引：1，他引：4  

F. Fitzko  P. Suhadolc  A. Aoudia  G.F. Panza   《Tectonophysics》2005,404(1-2):77-90

The 1511 Western Slovenia earthquake (M = 6.9) is the largest event occurred so far in the region of the Alps–Dinarides junction. Though it strongly influences the regional seismic hazard assessment, the epicenter and mechanism are still under debate. The complexity of the active tectonics of the Alps–Dinarides junction is reflected by the presence of both compressional and transpressional deformations. This complexity is witnessed by the recent occurrence of three main earthquake sequences, the 1976 Friuli thrust faulting events, the 1998 Bovec–Krn Mountain and the 2004 Kobarid strike-slip events. The epicenters of the 1998 and 2004 strike-slip earthquakes (M_s = 5.7 and M_s = 4.9, respectively) lie only 50 km far from the 1976 thrust earthquake (M_s = 6.5).We use the available macroseismic data and recent active tectonics studies, to assess a possible epicenter and mechanism for the 1511 earthquake and causative fault. According with previous works reported in the literature, we analyze both a two-and a single-event case, defining several input fault models. We compute synthetic seismograms up to 1 Hz in an extended-source approximation, testing different rupture propagations and applying a uniform seismic moment distribution on the fault segments. We extract the maximum horizontal velocities from the synthetics and we convert them into intensities by means of an empirical relation. A rounded-to-integer misfit between observed and computed intensities is performed, considering both a minimized and a maximized databases, built to avoid the use of half-degree macroseismic intensity data points. Our results are consistent with a 6.9 magnitude single event rupturing 50 km of the Idrija right-lateral strike-slip fault with bilateral rupture propagation.  相似文献   

Classification of seismic patterns in a hierarchical model of rupture: a new phase diagram for seismicity     

Clément Narteau 《Geophysical Journal International》2007,168(2):710-722

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A geodetic study of the 2003 January 22 Tecomán, Colima, Mexico earthquake     

Stuart V. Schmitt  Charles DeMets  J. Stock  O. Sánchez  B. Márquez-Azúa  G. Reyes 《Geophysical Journal International》2007,169(2):389-406

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Reply to comment by A. Douglas on 'Systematic determination of earthquake rupture directivity and fault planes from analysis of long-period P-wave spectra'     

Linda M. Warren  Peter M. Shearer 《Geophysical Journal International》2007,169(2):506-506

We respond to the comments by Douglas regarding our earlier paper by emphasizing that our automated method was intended to distinguish between the primary and auxiliary fault planes in earthquake focal mechanisms and does not always produce reliable results for rupture velocity and rupture length.  相似文献   

Estimating recurrence times and seismic hazard of large earthquakes on an individual fault     

G. Zöller  Y. Ben-Zion  M. Holschneider  S. Hainzl 《Geophysical Journal International》2007,170(3):1300-1310

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Coseismic rotation changes from the 2004 Sumatra earthquake: the effects of Earth's compressibility versus earthquake induced topography     

Roberto Sabadini  Riccardo E. M. Riva  Giorgio Dalla Via 《Geophysical Journal International》2007,171(1):231-243

Polar motion is modelled for the large 2004 Sumatra earthquake via dislocation theory for an incompressible elastic earth model, where inertia perturbations are due to earthquake-triggered topography of density–contrast interfaces, and for a compressible model, where inertia perturbation due to compression-dilatation of Earth's material is included; density and elastic parameters are based on a multilayered reference Earth. Both models are based on analytical Green's functions, propagated from the centre to the Earth's surface. Preliminary and updated seismological solutions are considered in elucidating the effects of improving earthquake parameters on polar motion. The large Sumatra thrust earthquake was particularly efficient in driving polar motion since it was responsible for large material displacements occurring orthogonally to the strike of the earthquake and to the Earth's surface, as imaged by GRACE gravity anomalies over the earthquake area. The effects of earthquake-induced topography are four times larger than the effects of Earth's compressibility, for l = 2 geopotential components. For varying compressional Earth properties and seismic solution, modelled polar motion ranges from 8.6 to 9.4 cm in amplitude and between 117° and 130° east longitude in direction. The close relationship between polar motion direction, earthquake longitude and thrust nature of the event, are established in terms of basic physical concepts.  相似文献