全文获取类型
| 收费全文 | 137篇 |
| 免费 | 10篇 |
| 国内免费 | 2篇 |
专业分类
| 地球物理 | 51篇 |
| 地质学 | 25篇 |
| 综合类 | 4篇 |
| 自然地理 | 69篇 |
出版年
| 2022年 | 1篇 |
| 2018年 | 3篇 |
| 2017年 | 1篇 |
| 2016年 | 2篇 |
| 2014年 | 1篇 |
| 2013年 | 2篇 |
| 2012年 | 1篇 |
| 2011年 | 4篇 |
| 2010年 | 3篇 |
| 2009年 | 6篇 |
| 2008年 | 7篇 |
| 2007年 | 12篇 |
| 2006年 | 6篇 |
| 2005年 | 12篇 |
| 2004年 | 6篇 |
| 2003年 | 13篇 |
| 2002年 | 5篇 |
| 2001年 | 6篇 |
| 2000年 | 9篇 |
| 1999年 | 9篇 |
| 1998年 | 4篇 |
| 1997年 | 4篇 |
| 1996年 | 6篇 |
| 1995年 | 4篇 |
| 1994年 | 2篇 |
| 1993年 | 5篇 |
| 1992年 | 3篇 |
| 1991年 | 3篇 |
| 1990年 | 1篇 |
| 1989年 | 5篇 |
| 1988年 | 1篇 |
| 1987年 | 1篇 |
| 1986年 | 1篇 |
排序方式： 共有149条查询结果，搜索用时 15 毫秒
41.
Rodolfo Console Rita Di Giovambattista Aldo Di Sanza Paolo Favali Giuseppe Smriglio 《Geophysical Journal International》2000,143(1):129-141
In this paper we show how the performance of the joint hypocentre determination (JHD) method can be improved, leading to reduced instability in cases close to singularity. The method has been extended by imposing a number of constraints introduced by other authors, and adding a new one. We tested the stability of the method and the relative advantages of the various constraints by simulating a geometrical space distribution of hypocentres recorded by a regional seismic network. We then applied this method to deep earthquakes that occurred in the Southern Tyrrhenian Sea subduction zone and to the seismicity of the Northern Apennines, which is moderately deeper than the typical shallow seismicity of the Apennines. The results obtained from the analysis of synthetic data and actual earthquakes confirm that the JHD method produces less scatter in the hypocentral determinations with respect to the standard locations. The main conclusion of our study is that we can significantly reduce the systematic mislocations that result from applying JHD to very clustered seismicity if we introduce the appropriate set of constraints. 相似文献
42.
43.
The epicentral tract of the great Assam earthquake of 1897 of magnitude 8·7 was monitored for about 6 months using an array
of portable seismographs. The observed seismicity pattern shows several diversely-oriented linear trends, some of which either
encompass or parallel known geological faults. A vast majority of the recorded micro-earthquakes had estimated focal depths
between 8–14 km. The maximum estimated depth was 45 km. On the basis of a seismic velocity model for the region reported recently
and these depth estimates we suggest that the rupture zone of the great 1897 earthquake had a depth of 11–12 km under the
western half of the Shillong massif. Four composite fault plane solutions define the nature of dislocation in three of the
seismic zones. Three of them show oblique thrusting while one shows pure dip slip reverse faulting. The fault plane solutions
fit into a regional pattern of a belt of earthquakes extending in NW-SE direction across the north eastern corner of the Bengal
basin. The maximum principle stress axis is approximately NS for all the solutions in conformity with the inferred direction
of the Indian-EuroAsian plate convergence in the eastern Himalaya. 相似文献
44.
IntroductionThesouthernpartofKhorasanProvinceineast-centralIranisoneoftheseismicallyactiveregionsintheMiddleeast.Historicalreportsindicatedseveralearthquakeshavecausedseveredestructionsandhumanlossinthisregionduringthepastcenturies(Ambraseys,Melville,1982).Theinstrumentallyrecordedearthquakesaswellastheexistenceofseveralactivefaultsalsosug-gestedthattheregionhadahighpotentialofseismicactivities.OnMay10,1997at07:57:29.6GMT,12:27:29.6localtime,ashallowdestructiveearthquakewithoutanyfeltfores… 相似文献
45.
Relocation and assessment of seismicity in the Iran region 总被引：11，自引：0，他引：11
46.
Strong seismic events once again confirm the view that great destructive earthquakes are produced by the reactivation of pre-existing
faults although they have usually remained inactive for many, perhaps thousands of years. It is evident that such active seismogenic
zones, with little or no seismicity, have presumably been ignored in the determination of the region's seismic hazard.
At south Peloponnesus, Greece, is situated at Taygetos mountain. At its eastern front lies a large normal fault system, the
southern segment being the Sparta fault. This area has been characterized by low seismicity for the last 25 centuries. However,
during the 6th and 5th centuries B.C. several destructive earthquakes have been reported. That of 464 B.C., was the most destructive
and devastated the city of Sparta. Detailed morphotectonic observations of this area, suggest that the earthquake of 464 B.C.
could be related to the most recent reactivation of this fault.
The ground accelerations that would be produced by a future activation of the Sparta fault, were calculated, by applying a
method which takes into account information mainly from the seismotectonic parameters of the Sparta fault, the rupture pattern,
the properties of the propagation medium and the local ground conditions. Moreover, these results were compared with those
of other independent studies based mainly on the seismic data of the area. This method estimated greater expected values of
ground acceleration than those computed by the conventional seismic hazard methods. The highest values correspond to the activation
of the Sparta fault either in a unilateral rupture, which would start from the southernmost point of the fault, or in a circular
one. Furthermore, an increase is observed of the order of 50% in the ground acceleration values in unconsolidated soft ground
in relation to the corresponding values of hard ground.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
47.
Variations of stress directions in the western Alpine arc 总被引：4，自引：0，他引：4
48.
P. Knoll G. Kowalle K. Rother B. Schreiber I. Paskaleva 《Pure and Applied Geophysics》1996,147(2):389-407
By analysis of microtremors recorded with digital seismological monitoring equipment near the Provadia salt diapir (Bulgaria), two groups of events showing different characteristics have been detected in the vicinity of the salt production area. The first group of events has low magnitudes and is located at a distance of about 1 km from the top of the salt diapir. These events show low stress drops. The second group of tremors is located outside the salt diapir. The corresponding magnitudes and stress drops are larger. The first class of events seems to be related to processes at the contour of the salt leaching caverns, whereas the origin of the second group seems to be connected with stress redistribution processes around the salt body. Based on this analysis, the tectonic model of the Provadia salt diapir has been modified. 相似文献
49.
50.
Large earthquakes in the macquarie ridge complex: Transitional tectonics and subduction initiation 总被引：1，自引：0，他引：1
Larry J. Ruff Jeffrey W. Given Chris O. Sanders Christine M. Sperber 《Pure and Applied Geophysics》1989,129(1-2):71-129
While most aspects of subduction have been extensively studied, the process of subduction initiation lacks an observational foundation. The Macquarie Ridge complex (MRC) forms the Pacific-Australia plate boundary between New Zealand to the north and the Pacific-Australia-Antarctica triple junction to the south. The MRC consists of alternating troughs and rises and is characterized by a transitional tectonic environment in which subduction initiation presently occurs. There is a high seismicity level with 15 large earthquakes (M>7) in this century. Our seismological investigation is centered on the largest event since 1943: the 25 MAY 1981 earthquake. Love, Rayleigh, andP waves are inverted to find: a faulting geometry of right-lateral strike-slip along the local trend of the Macquarie Ridge (N30°E); a seismic moment of 5×1027 dyn cm (M
w=7.7) a double event rupture process with a fault length of less than 100km to the southwest of the epicenter and a fault depth of less than 20km. Three smaller thrust earthquakes occurred previous to the 1981 event along the 1981 rupture zone; their shallow-dipping thrust planes are virtually adjacent to the 1981 vertical fault plane. Oblique convergence in this region is thus accommodated by a dual rupture mode of several small thrust events and a large strike-slip event. Our study of other large MRC earthquakes, plus those of other investigators, produces focal mechanisms for 15 earthquakes distributed along the entire MRC; thrust and right-lateral strike-slip events are scattered throughout the MRC. Thus, all of the MRC is characterized by oblique convergence and the dual rupture mode. The true best-fit rotation pole for the Pacific-Australia motion is close to the Minster & Jordan RM2 pole for the Pacific-India motion. Southward migration of the rotation pole has caused the recent transition to oblique convergence in the northern MRC. We propose a subduction initiation process that is akin to crack propagation; the 1981 earthquake rupture area is identified as the crack-tip region that separates a disconnected mosaic of small thrust faults to the south from a horizontally continuous thrust interface to the north along the Puysegur trench. A different mechanism of subduction initiation occurs in the southernmost Hjort trench region at the triple junction. newly created oceanic lithosphere has been subducted just to the north of the triple junction. The entire MRC is a soft plate boundary that must accommodate the plate motion mismatch between two major spreading centers (Antarctica-Australia and Pacific-Antarctica). The persistence of spreading motion at the two major spreading centers and the consequent evolution of the three-plate system cause the present-day oblique convergence and subduction initiation in the Macquarie Ridge complex. 相似文献