Structural Properties and Deformation Patterns of Evolving Strike-slip Faults: Numerical Simulations Incorporating Damage Rheology   总被引：1，自引：0，他引：1  

Yaron Finzi  Elizabeth H. Hearn  Yehuda Ben-Zion  Vladimir Lyakhovsky 《Pure and Applied Geophysics》2009,166(10-11):1537-1573

We present results on evolving geometrical and material properties of large strike-slip fault zones and associated deformation fields, using 3-D numerical simulations in a rheologically-layered model with a seismogenic upper crust governed by a continuum brittle damage framework over a viscoelastic substrate. The damage healing parameters we employ are constrained using results of test models and geophysical observations of healing along active faults. The model simulations exhibit several results that are likely to have general applicability. The fault zones form initially as complex segmented structures and evolve overall with continuing deformation toward contiguous, simpler structures. Along relatively-straight mature segments, the models produce flower structures with depth consisting of a broad damage zone in the top few kilometers of the crust and highly localized damage at depth. The flower structures form during an early evolutionary stage of the fault system (before a total offset of about 0.05 to 0.1 km has accumulated), and persist as continued deformation localizes further along narrow slip zones. The tectonic strain at seismogenic depths is concentrated along the highly damaged cores of the main fault zones, although at shallow depths a small portion of the strain is accommodated over a broader region. This broader domain corresponds to shallow damage (or compliant) zones which have been identified in several seismic and geodetic studies of active faults. The models produce releasing stepovers between fault zone segments that are locations of ongoing interseismic deformation. Material within the fault stepovers remains damaged during the entire earthquake cycle (with significantly reduced rigidity and shear-wave velocity) to depths of 10 to 15 km. These persistent damage zones should be detectable by geophysical imaging studies and could have important implications for earthquake dynamics and seismic hazard.  相似文献   

Fluvial incision and coarse gravel redistribution across the modern Dead Sea shelf as a result of base-level fall     

Haggai Eyal  Elad Dente  Itai Haviv  Yehouda Enzel  Thomas Dunne  Nadav G. Lensky 《地球表面变化过程与地形》2019,44(11):2170-2185

Global eustatic lowstands can expose vast areas of continental shelves, and occasionally the shelf edge and the continental slope. The degree of fluvial connectivity to receding shores influences the redistribution of sediments across these emerging landscapes. Shelf and slope emergence in the Dead Sea since the middle of the 20th century, offers a rare opportunity to examine evolution of stream connectivity in response to continuous base-level decline. We characterize the connectivity evolution of two streams, using high-resolution time series of aerial imagery and elevation models, field mapping, and grain-size analyses. Our rich spatiotemporal dataset of evolving channel geomorphology, sediment transport conditions, and sediment redistribution, allows calculating potential coarse sediment mobility in response to base level decline. Following shelf emergence, alluvial fans first prograded onto the low-gradient shelf under unfavourable conditions for transporting coarse sediment to the regressing shoreline. Then, with shelf and slope emergence, the two adjacent streams evolved differently. The smaller, more arid watershed still maintains its highstand delta progradation on the shelf and is practically disconnected from the receding lake. The larger catchment, heading in wetter environments and having a narrower shelf, has incised the shelf and renewed and gradually intensified the sediment transport from the highstand to the lowstand delta. Sediment mobilization to lowstand shorelines is controlled by the evolution of the channel profile and by the average speed of gravel transport (10s-100s m yr^-1). These findings from the Dead Sea are relevant to fluvial processes operating on continental shelves during glacial maxima. Streams would have commonly stored high proportions of their coarse sediment on the continental shelves rather than efficiently connecting with the lowstand level. Additionally, differences in sediment routing patterns should exist among nearby streams, primarily due to continental margin geometry and watershed hydrology. © 2019 John Wiley & Sons, Ltd.  相似文献   

Dynamic Ruptures on a Frictional Interface with Off-Fault Brittle Damage: Feedback Mechanisms and Effects on Slip and Near-Fault Motion     

Shiqing Xu  Yehuda Ben-Zion  Jean-Paul Ampuero  Vladimir Lyakhovsky 《Pure and Applied Geophysics》2015,172(5):1243-1267

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Systematic Receiver Function Analysis of the Moho Geometry in the Southern California Plate-Boundary Region     

Yaman Ozakin  Yehuda Ben-Zion 《Pure and Applied Geophysics》2015,172(5):1167-1184

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Constrained simulations of the local universe – II. The nature of the local Hubble flow     

Luis A. Martinez-Vaquero  Gustavo Yepes  Yehuda Hoffman  Stefan Gottlöber  Mira Sivan 《Monthly notices of the Royal Astronomical Society》2009,397(4):2070-2080

Using a suite of N -body simulations in different cold dark matter (CDM) scenarios, with cosmological constant (ΛCDM) and without (OCDM, SCDM), we study the Hubble flow (σ_H) in Local Volumes (LV) around Local Group (LG) like objects found in these simulations, and compare the numerical results with the most recent observations. We show that ΛCDM and OCDM models exhibit the same behaviour of σ_H. Hence, we demonstrate that the observed coldness of the Hubble flow is not likely to be a manifestation of the dark energy, contrary to previous claims. The coldness does not constitute a problem by itself but it poses a problem to the standard ΛCDM model only if the mean density within the LV is greater than twice the mean matter cosmic density. The lack of blueshifted galaxies in the LV, outside of the LG can be considered as another manifestation of the coldness of the flow. Finally, we show that the main dynamical parameter that affects the coldness of the flow is the relative isolation of the LG, and the absence of nearby Milky Way like objects within a distance of about  3 Mpc  .  相似文献   

The Elastic Strain Energy of Damaged Solids with Applications to Non-Linear Deformation of Crystalline Rocks     

Yariv?HamielEmail author  Vladimir?Lyakhovsky  Yehuda?Ben-Zion 《Pure and Applied Geophysics》2011,168(12):2199-2210

Laboratory and field data indicate that rocks subjected to sufficiently high loads clearly deviate from linear behavior. Non-linear stress–strain relations can be approximated by including third and higher-order terms of the strain tensor in the elastic energy expression (e.g., the Murnaghan model). Such classical non-linear models are successful for calculating deformation of soft materials, for example graphite, but cannot explain with the same elastic moduli small and large non-linear deformation of stiff rocks, such as granite. The values of the third (higher-order) Murnaghan moduli estimated from acoustic experiments are one to two orders of magnitude above the values estimated from stress–strain relations in quasi-static rock-mechanics experiments. The Murnaghan model also fails to reproduce an abrupt change in the elastic moduli upon stress reversal from compression to tension, observed in laboratory experiments with rocks, concrete, and composite brittle material samples, and it predicts macroscopic failure at stress levels lower than observations associated with granite. An alternative energy function based on second-order dependency on the strain tensor, as in the Hookean framework, but with an additional non-analytical term, can account for the abrupt change in the effective elastic moduli upon stress reversal, and extended pre-yielding deformation regime with one set of elastic moduli. We show that the non-analytical second-order model is a generalization of other non-classical non-linear models, for example “bi-linear”, “clapping non-linearity”, and “unilateral damage” models. These models were designed to explain the abrupt changes of elastic moduli and non-linearity of stiff rocks under small strains. The present model produces dilation under shear loading and other non-linear deformation features of the stiff rocks mentioned above, and extends the results to account for gradual closure of an arbitrary distribution of initial cracks. The results provide a quantitative framework that can be used to model simultaneously, with a small number of coefficients, multiple observed aspects of non-linear deformation of stiff rocks. These include, in addition to the features mentioned above, stress-induced anisotropy and non-linear effects in resonance experiments with damaged materials.  相似文献   

Is Eilat-Aqaba a bi-national city? Can economic opportunities overcome the barriers of politics and psychology?     

Yehuda Gradus 《GeoJournal》2001,54(1):85-99

Unlike other bi-national cities, Eilat and Aqaba constitute a special case in which the interaction between the two cities is dependent upon external factors, mainly of a political nature. Eilat in Israel and Aqaba in Jordan straddle each side of the Gulf of Aqaba. Both are similar from a functional aspect: they are port and tourism towns and both constitute a gateway to east Africa and the Far East. They are both situated in a desert region near a sea. The Oslo Accords and subsequently the peace agreement between Jordan and Israel, have opened up many possibilities for cooperation and joint development activity. A number of projects have been put forward, including a joint airport aimed at serving both cities, as well as the shared use of the seaports. Tour packages from Europe to both cities are another feature that holds a substantial economic potential, as do connecting roads and joint plans for the preservation of the unique landscape in this region. A border-crossing point between the two countries has been opened up and tens of thousands of tourists have flocked (mostly from Israel) to visit nearby Petra and Wadi Ram. Laborers from Jordan have begun to be seen in Eilat, working mostly in construction. The long history of the Arab-Israeli conflict is still casting a heavy shadow on the great possibilities for cooperation. The signing of a peace treaty is a necessary but not a sufficient condition for the bringing about of cooperation in the field. The enmity and the military activity between Israel and the Palestinians, especially during recent months since the outbreak the intifada for the second time, have resulted in a drastic decline in cooperation that started initially at a slow and hesitant pace following the signing of the peace treaty with Jordan (1994). The fact that about 60% of the Jordanian population is of Palestinian origin, causes the Jordanian government to maintain a cautious stance in promoting cooperation with Israel. Thus, the development of Eilat and Aqaba as a bi-national city is, to a great extent, dependent on the advancement of the peace process between Israel and all its Arab neighbors, and especially on the outcome of the Israeli-Palestinian conflict. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Limitation of using multi-type sensors in combination for verifying atmospheric phenomena     

S. Egert  E. Eyal  J. Sivan  R. Reichman 《Boundary-Layer Meteorology》1993,62(1-4):385-391

The feasibility of combining two sensors for monitoring gas concentrations over a large area, is demonstrated via controlled simulation experiments. The network considered was a lidar combined with a point detector—the MIRAN spectrophotometer equipped with a flow-through gas cell. The first has a spatial scanning capacity and a very good time resolution, whereas the second has an inherent temporal memory effect. Algorithms for operating the two sensors coincidentally, taking their physical characteristics into account, were constructed. A good fit was found between measured concentrations in the MIRAN and reconstructed concentrations, using the lidar data for the same environment. Thus complementary operation can be achieved. The MIRAN temporal memory effect can be overcome by correlating the concentration calculated over different time intervals.  相似文献   

Triple-frequency GPS precise point positioning with rapid ambiguity resolution   总被引：10，自引：6，他引：4  

Jianghui Geng  Yehuda Bock 《Journal of Geodesy》2013,87(5):449-460

At present, reliable ambiguity resolution in real-time GPS precise point positioning (PPP) can only be achieved after an initial observation period of a few tens of minutes. In this study, we propose a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time PPP. Specifically, extra-wide-lane ambiguity resolution can be first achieved almost instantaneously with the Melbourne-Wübbena combination observable on L2 and L5. Then the resultant unambiguous extra-wide-lane carrier-phase is combined with the wide-lane carrier-phase on L1 and L2 to form an ionosphere-free observable with a wavelength of about 3.4 m. Although the noise of this observable is around 100 times the raw carrier-phase noise, its wide-lane ambiguity can still be resolved very efficiently, and the resultant ambiguity-fixed observable can assist much better than pseudorange in speeding up succeeding narrow-lane ambiguity resolution. To validate this method, we use an advanced hardware simulator to generate triple-frequency signals and a high-grade receiver to collect 1-Hz data. When the carrier-phase precisions on L1, L2 and L5 are as poor as 1.5, 6.3 and 1.5 mm, respectively, wide-lane ambiguity resolution can still reach a correctness rate of over 99 % within 20 s. As a result, the correctness rate of narrow-lane ambiguity resolution achieves 99 % within 65 s, in contrast to only 64 % within 150 s in dual-frequency PPP. In addition, we also simulate a multipath-contaminated data set and introduce new ambiguities for all satellites every 120 s. We find that when multipath effects are strong, ambiguity-fixed solutions are achieved at 78 % of all epochs in triple-frequency PPP whilst almost no ambiguities are resolved in dual-frequency PPP. Therefore, we demonstrate that triple-frequency PPP has the potential to achieve ambiguity-fixed solutions within a few minutes, or even shorter if raw carrier-phase precisions are around 1 mm. In either case, we conclude that the efficiency of ambiguity resolution in triple-frequency PPP is much higher than that in dual-frequency PPP.  相似文献   

Secondary infall and dark matter haloes     

Yago Ascasibar  Yehuda Hoffman  Stefan Gottlöber 《Monthly notices of the Royal Astronomical Society》2007,376(1):393-404

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