Three-dimensional elastic earthquake modelling based on integrated seismological and InSAR data: the M_w= 7.2 Nuweiba earthquake, gulf of Elat/Aqaba 1995 November     

G. Shamir  G. Baer  A. Hofstetter 《Geophysical Journal International》2003,154(3):731-744

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Source mechanism of the 22/11/1995 Gulf of Aqaba earthquake and its aftershock sequence     

A. Hofstetter  H.K. Thio  G. Shamir 《Journal of Seismology》2003,7(1):99-114

The Gulf of Aqaba earthquake occurred on 22/11/1995 with M _W = 7.2 and was the largest event to occur along the Dead Sea Transform in at least a century. We determined the source mechanism of the event based on the inversion of the P and SH waveforms observed by teleseismic stations. Our solution consists of 2 similar subevents, where the first exhibits a left-lateral strike-slip motion with a normal component and the second subevent shows an almost pure left-lateral strike-slip motion along the gulf major fault system. The total seismic moment is 7.7 × 10²⁶ dyne-cm, with source duration of 15 seconds. The aftershock sequence was recorded by the regional broad band stations BGIO and JER, of the Israel Seismic Network, and KEG, of the MEDNET regional network for earthquakeswith M _W > 4.0. Aftershock epicenter seems to cluster mainly in the Eilat basin and the Aragonese basin. The dominant mechanism indicates left-lateral strike slip motion along the gulf trend, similar to the mainshock.  相似文献   

A smoothed cap model for variably saturated soils and its robust numerical implementation          下载免费PDF全文

P. Gamnitzer  G. Hofstetter 《国际地质力学数值与分析法杂志》2015,39(12):1276-1303

This paper deals with the numerical implementation of a cap model for unsaturated soils. It provides a brief review of existing cap model approaches, based on which an improved model formulated in terms of generalised effective stress and matric suction is derived and described in detail. Although the proposed model is a multisurface plasticity model, it can efficiently be implemented using only single‐surface projections because of the smoothness of the model, which is obtained by construction. Numerical algorithms are provided for these single‐surface stress projections, using a single‐equation approach whenever possible. The robustness of the utilised single‐equation approaches is enhanced by proposing problem‐fitted start‐up procedures based on investigations of the nonlinear projection equations. A comparison of the model response with extensive material test data is used to validate the model and to demonstrate the robust application of the approach to silty sands and low to medium plasticity clays. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Review and enhancement of 3D concrete models for large‐scale numerical simulations of concrete structures     

B. Valentini  G. Hofstetter 《国际地质力学数值与分析法杂志》2013,37(3):221-246

The present paper focuses on selected plasticity and damage‐plasticity models for describing the 3D material behavior of concrete. In particular, a plasticity model and a damage‐plasticity model are reviewed and evaluated. Based on the results of the evaluation, enhancements are proposed, aiming at improving the correspondence between predicted and observed material behavior and aiming at implementing a robust and efficient stress update algorithm in a finite element program for performing large‐scale 3D numerical simulations of concrete structures. The capabilities of the concrete models are demonstrated by 3D numerical simulations of benchmark tests with combined bending and torsional loading and combined compression and shear loading and by a large‐scale 3D finite element analysis of a model test of a concrete arch dam. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Der Einfluß meteorologischer Faktoren auf die Temperatur alpiner Seen     

G. Hofstetter 《Theoretical and Applied Climatology》1954,5(2):146-181

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Dark energy in five-dimensional Brans-Dicke cosmology with dimensional reduction     

Ahmad Rami El-Nabulsi 《中国天文和天体物理学报》2011,(8)

We explore a 5D Brans-Dicke scalar cosmology by conjecturing that the four-dimensional Hubble parameter varies as H = εφs,ε∈ R and s is some unknown power index and that the extra-dimensions compactify as the visible dimensions expand as b(t) ≈ ax(t) ,x ∈ R-. We mainly discuss the case x =-1. For critical values of ε close to unity,it was observed that the acceleration of the universe occurs at redshift close to z = 0.8 which indicates that in our model,accelerated expansion of the universe began only recen...  相似文献   

D-Dimensional non-singular universe dominated by dark energy     

Ahmad Rami El-Nabulsi 《Astrophysics and Space Science》2011,332(1):37-42

We investigate the late-time dynamics of a four-dimensional universe based on the effective action of a Brans-Dicke scalar field in the presence of the matter source term, conformal coupling of the scalar curvature to the scalar field, a dynamical cosmological constant and Gauss-Bonnet higher-order terms in the scalar curvature. Many new interesting features are revealed and discussed in some details.  相似文献   

Active tectonic morphology and submarine deformation of the northern Gulf of Eilat/Aqaba from analyses of multibeam data   总被引：1，自引：0，他引：1  

Gideon Tibor  Tina M. Niemi  Zvi Ben-Avraham  Abdallah Al-Zoubi  Ronnie A. Sade  John K. Hall  Gal Hartman  Emad Akawi  Abdelrahmem Abueladas  Rami Al-Ruzouq 《Geo-Marine Letters》2010,30(6):561-573

A high-resolution marine geophysical study was conducted during October-November 2006 in the northern Gulf of Aqaba/Eilat, providing the first multibeam imaging of the seafloor across the entire gulf head spanning both Israeli and Jordanian territorial waters. Analyses of the seafloor morphology show that the gulf head can be subdivided into the Eilat and Aqaba subbasins separated by the north-south-trending Ayla high. The Aqaba submarine basin appears starved of sediment supply, apparently causing erosion and a landward retreat of the shelf edge. Along the eastern border of this subbasin, the shelf is largely absent and its margin is influenced by the Aqaba Fault zone that forms a steep slope partially covered by sedimentary fan deltas from the adjacent ephemeral drainages. The Eilat subbasin, west of the Ayla high, receives a large amount of sediment derived from the extensive drainage basins of the Arava Valley (Wadi ’Arabah) and Yutim River to the north–northeast. These sediments and those entering from canyons on the south-western border of this subbasin are transported to the deep basin by turbidity currents and gravity slides, forming the Arava submarine fan. Large detached blocks and collapsed walls of submarine canyons and the western gulf margin indicate that mass wasting may be triggered by seismic activity. Seafloor lineaments defined by slope gradient analyses suggest that the Eilat Canyon and the boundaries of the Ayla high align along north- to northwest-striking fault systems—the Evrona Fault zone to the west and the Ayla Fault zone to the east. The shelf–slope break that lies along the 100 m isobath in the Eilat subbasin, and shallower (70–80 m isobaths) in the Aqaba subbasin, is offset by approx. 150 m along the eastern edge of the Ayla high. This offset might be the result of horizontal and vertical movements along what we call the Ayla Fault on the east side of the structure. Remnants of two marine terraces at 100 m and approx. 150 m water depths line the southwest margin of the gulf. These terraces are truncated by faulting along their northern end. Fossil coral reefs, which have a similar morphological appearance to the present-day, basin margin reefs, crop out along these deeper submarine terraces and along the shelf–slope break. One fossil reef is exposed on the shelf across the Ayla high at about 60–63 m water depth but is either covered or eroded in the adjacent subbasins. The offshore extension of the Evrona Fault offsets a fossil reef along the shelf and extends south of the canyon to linear fractures on the deep basin floor.  相似文献   

Life and habitable zones in the Universe     

Rami T.F. Rekola 《Planetary and Space Science》2009,57(4):430-433

Currently we are aware of only one biosphere in the entire Universe, our own. Various ongoing observational programmes are, however, attempting to locate more. These searches for extraterrestrial life are among the most challenging and interesting tasks of modern science. The Universe is immense, and even the distances to the nearest stars are beyond our present capabilities to traverse, so that search strategies must be thought through carefully in terms of how, where and what to search for. Life is undoubtedly more likely in some environments than others, and environmental criteria must be fulfilled for life to arise, survive, evolve and thrive. As search resources are limited we should concentrate our search on habitable zones that are suitable for the kind of life we can most easily recognise, in other words, searches should be guided by our own biosphere.  相似文献   

Detailed seismicity analysis revealing the dynamics of the southern Dead Sea area     

B. Braeuer  G. Asch  R. Hofstetter  Ch. Haberland  D. Jaser  R. El-Kelani  M. Weber 《Journal of Seismology》2014,18(4):731-748

Within the framework of the international DESIRE (DEad Sea Integrated REsearch) project, a dense temporary local seismological network was operated in the southern Dead Sea area. During 18 recording months, 648 events were detected. Based on an already published tomography study clustering, focal mechanisms, statistics and the distribution of the microseismicity in relation to the velocity models from the tomography are analysed. The determined b value of 0.74 leads to a relatively high risk of large earthquakes compared to the moderate microseismic activity. The distribution of the seismicity indicates an asymmetric basin with a vertical strike-slip fault forming the eastern boundary of the basin, and an inclined western boundary, made up of strike-slip and normal faults. Furthermore, significant differences between the area north and south of the Bokek fault were observed. South of the Bokek fault, the western boundary is inactive while the entire seismicity occurs on the eastern boundary and below the basin-fill sediments. The largest events occurred here, and their focal mechanisms represent the northwards transform motion of the Arabian plate along the Dead Sea Transform. The vertical extension of the spatial and temporal cluster from February 2007 is interpreted as being related to the locking of the region around the Bokek fault. North of the Bokek fault similar seismic activity occurs on both boundaries most notably within the basin-fill sediments, displaying mainly small events with strike-slip mechanism and normal faulting in EW direction. Therefore, we suggest that the Bokek fault forms the border between the single transform fault and the pull-apart basin with two active border faults.  相似文献