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1.
针对地震活动与顶板事故进行时空序列统计分析,得出两点新认识:(1)顶板事故与宏观地震序列有较强的频率对应,似乎是"遥相呼应";(2)相当多的顶板事故伴随有周边小震发生。推测部分原因是这些矿井位于地震带附近,部分原因是采矿卸压引发矿震,一些地震可能是宏观地震序列中的一部分。如果能够掌握,并加以利用,对于安全生产具有一定意义:对既定煤田,查找周边对矿区地应力影响强烈的地震带或断裂带,这些矿井顶板事故有可能成为周边地震带或断裂带的"应力窗",而地震带或断裂带的活动又成为煤矿地质灾害的"晴雨表"。在煤田大区,可以把顶板事故群发当作构造应力扰动的一种反映,作为大区构造应力扰动传入矿区,再与开采卸压作用叠加,引起地质灾害的证据。 相似文献
2.
H.-J. Kuempel R. K. Chadha D. V. Ramana M. Ravi 《Journal of the Geological Society of India》2017,90(6):678-683
The filling of the Koyna reservoir in western India and the associated triggered earthquakes have been well documented. Several studies have suggested that earthquakes are triggered on pre-existing faults in the region due to changes in pore pressure caused by pore pressure diffusion. To study in-situ pore pressure variations twenty-one borewells were drilled in the Koyna-Warna region under an Indo-German research program during 1995–1998. In most of these wells tidal signals are observed in well level variations indicating sensitivity to small strain changes in hydraulically connected, confined aquifers. Those signals, hence, are suitable to reflect variations in the stress field of local rock formations. More than a decade of well level monitoring has shown four types of earthquake related changes. The pre- and post-earthquake changes are mostly interpretative in nature and difficult to substantiate. The co-seismic and transient changes which are observed for local and large teleseismic events are well established. Wells connected to unconfined aquifers also showed changes related to seismicity in case of large magnitude earthquakes at closer distances. Some anomalous water level fluctuations are seen which are not associated with local or teleseismic earthquakes. These changes are coherent in nature and reflect aseismic regional volume strain. 相似文献
3.
N. G. Tomilin 《Russian Journal of Pacific Geology》2009,3(5):470-476
The areas of strong paired earthquakes, including the Simushir ones, have been defined on the basis of the kinetic concepts
of the strength of the solids, the multilevel rock structure, and the related hierarchical model of the rock fracture. The
analysis of the spatiotemporal kinetics of these areas did not show any physical difference as compared to the preparation
for the single events. 相似文献
4.
沂沭断裂带及其近区的地震成因岩石新认识 总被引：4，自引：1，他引：4
将沂沭断裂带及其附近地区的地震成因岩石划分为四种类型,它们是具有地震成因构造的震积岩、震断层构造岩、震火山岩及隐爆地震角砾岩.前两类是构造地震的记录,而后两类是火山地震及隐爆火山地震的记录.由于震断层构造岩沿长期活动性断层分布,大多遭受了若干期强地震活动的改造,所以不易确定其最初的形成时期.因此,笔者重点对分布于沂沭断裂地震带及附近的其它三类地震成因岩石(包括震积岩、震火山岩和隐爆地震角砾岩)作了研究,论述了三类地震成因岩石的特征、时空分布、反映的地震作用机理及意义.认为:地震成因岩石不仅是强地震事件和激烈构造活动的记录;而且,因为由强地震形成的不同等级断层和裂隙构成了一个高渗透性的能够沟通不同深度石油和成矿流体的网络,所以深入研究地震成因岩石有助于完善大断裂地震带及近区的石油聚集与成矿理论. 相似文献
5.
H. Daniel Stillwell 《Natural Hazards》1992,6(2):131-159
Natural hazards and disasters occur widely throughout the world. Disasters can be costly both in terms of human lives and property and ecosystem disruption. Higher death tolls in developing nations may be the result of poverty, rapid population growth, urbanization, and inadequate communication facilities. The purpose of this study is to show patterns of major catastrophic events in Latin America so that their impacts can be evaluated and compared.Latin America was selected because of the variety of recent events commanding wide attention: earthquakes in Mexico, volcanic eruptions in Colombia, hurricanes and floods in Haiti, and drought and mudflows in Brazil. Spatial and temporal aspects of natural disasters are presented in nine tables and 21 maps. The tables give selected disaster data by country for volcanic eruptions, earthquakes, landslides, and atmospheric disturbances from the 16th century to 1989. Most data is derived from disasters occurring during the 20th century and include number of events, people killed, people affected, and U.S.$ damage. Maps show environmental settings for disasters and allow detailed comparison among countries. Floods account for the greatest number of major events in the most countries, earthquakes cause the most deaths and damage, while droughts affect the most people. Peru surpasses all others in susceptibility to major disasters. Assessment of vulnerability to hazards, improved economic opportunities, and an increased social and political concern for poor people should help reduce future losses from natural disasters in Latin America. 相似文献
6.
山西云岗石窟侏罗系地震液化砂岩柱的发现及其大地构造意义 总被引：1，自引：0，他引：1
本文主要报道在华北克拉通北缘云岗石窟景区内侏罗系地层中发现的20余个由地震液化形成的砂岩柱。地震导致的砂土液化是非常普遍的自然现象,地震波的震动使埋藏在地下未固结的饱和砂质沉积物迅速变为流体并在巨大压力下喷涌至地表,形成砂火山或泥火山。2008年汶川8. 0级大地震和2012年新西兰6. 2级地震都产生了严重的液化现象,在对地表造成严重破坏的同时,分别在地表形成了一系列的溢出丘和形态完好的砂火山。古地震之后,液化砂质沉积物往往在上涌的通道内固结成岩,形成穿层的岩柱或岩管。近年来,美国科罗拉多大峡谷相继发现很多地震液化形成的中生代巨型碎屑岩柱。2018年,本文作者在云岗石窟景区内的侏罗系云岗组中发现了20多条直径15~20cm左右、高可达2m以上穿层“侵入”的砂岩柱,有的在纵向上呈串珠状排列,有的呈不规则的树枝状自下向上伸展,膨大狭缩、分支复合现象非常明显,砂岩柱内部结构均一,不见任何层理。砂岩柱顶端的泥质围岩石中有明显向上牵引、拖拽的痕迹。这些砂岩柱没有任何硅化木的特征,也不是普通成岩作用形成的结核,与暴雨、泥石流、重力滑塌等作用均无任何关系,是古地震液化作用在地层内保存的遗迹,故称为液化砂岩柱。地震液化砂岩柱发育的层位位于李振宏等人(2014)在宁武—静乐盆地侏罗系云岗组顶部的凝灰质泥晶碳酸盐层位(160 Ma)之下约40m处,初步判定形成这些液化砂岩柱的古地震发生于160. 75 Ma~160 Ma之间的晚侏罗世。古地震的形成过程与燕山运动引起的地壳运动有直接的关联,是华北克拉通内与燕山运动伴生的古地震在地层中留下的最直接证据。 相似文献
7.
Mustafa Toker 《Central European Journal of Geosciences》2013,5(3):423-434
The Van earthquake (M W 7.1, 23 October 2011) in E-Anatolia is typical representative of intraplate earthquakes. Its thrust focal character and aftershock seismicity pattern indicate the most prominent type of compound earthquakes due to its multifractal dynamic complexity and uneven compressional nature, ever seen all over Turkey. Seismicity pattern of aftershocks appears to be invariably complex in its overall characteristics of aligned clustering events. The population and distribution of the aftershock events clearly exhibit spatial variability, clustering-declustering and intermittency, consistent with multifractal scaling. The sequential growth of events during time scale shows multifractal behavior of seismicity in the focal zone. The results indicate that the extensive heterogeneity and time-dependent strength are considered to generate distinct aftershock events. These factors have structural impacts on intraplate seismicity, suggesting multifractal and unstable nature of the Van event. Multifractal seismicity is controlled by complex evolution of crustal-scale faulting, mechanical heterogeneity and seismic deformation anisotropy. Overall seismicity pattern of aftershocks provides the mechanism for strain softening process to explain the principal thrusting event in the Van earthquake. Strain localization with fault weakening controls the seismic characterization of Van earthquake and contributes to explain the anomalous occurrence of aftershocks and intraplate nature of the Van earthquake. 相似文献
8.
This article is devoted to evaluating destructive earthquakes (magnitude >6) of Iran and determining properties of their source parameters. First of all, a database of documented earthquakes has been prepared via reliable references and causative faults of each event have been determined. Then, geometric parameters of each fault have been presented completely. Critical parameters such as Maximum Credible Rupture, MCR, and Maximum Credible Earthquake, MCE, have been compiled based on the geometrical parameters of the earthquake faults. The calculated parameters have been compared to the maximum earthquake and the surface rupture which have been recorded for the earthquake faults. Also, the distance between the epicenter of documented earthquake events and their causative faults has been calculated (the distance was less than 20 km for 90% of the data). Then, the distance between destructive earthquakes (with the magnitude more than 6) and the nearest active fault has been calculated. If the estimated distance is less than 20 km and the mechanism of the active fault and the event are reported the same, the active fault will be introduced as a probable causative fault of that earthquake. In the process, all of the available geological, tectonic, seismotectonic maps, aerial geophysical data as well as remote sensing images have been evaluated. Based on the quality and importance of earthquake data, the events have been classified into three categories: (1) the earthquakes which have their causative faults documented, (2) the events with magnitude higher than 7, and (3) the events with the magnitude between 6 and 7. For each category, related maps and tables have been compiled and presented. Some important faults and events have been also described throughout the paper. As mentioned in this paper, these faults are likely to be in high seismic regions with potential for large-magnitude events as they are long, deep and bound sectors of the margins characterized by different deformation and coupling rates on the plate interface. 相似文献
9.
Ronald T. Eguchi 《Natural Hazards》2013,68(1):201-202
Disaster experts around the world have continually warned governments and the public about the possibility of “worst-case” natural hazard scenarios and their overwhelming impacts. Yet, planning for the occurrence of these events has fallen far short of need. The large earthquake that occurred off the coast of Sumatra in 2004, which resulted in one of the deadliest tsunamis ever recorded, was a painful reminder that living in some of the most desirable areas of the world does have its risks. We all have enjoyed the fun of restful visits to coastal resort communities all around the world, and we rarely think about earthquakes or tsunamis interfering with this enjoyment. Yet, they take us by surprise. Before these events do occur, there should be adequate education for everyone on what actions are appropriate as well as an effective warning system to trigger the right actions. 相似文献
10.
11.
深源地震机理的研究有助于深入了解板块构造的驱动机制和动力学特征。对中国唯一的深震区--东北深震区的深震分布特征和震源机制解进行了综述和初步研究,初步探索了地震的发震机理、动力源以及地震的空间分布与西北太平洋俯冲板块的关系。分析结果显示：（1）震源深度在SEE NWW方向上有依次加深的趋势,而在SSW NNE方向上却没有明显变化,震源机制解的应力状态以下倾的压缩应力为主,说明中国东北深震的发生与西北太平洋板块向欧亚大陆的俯冲直接相关;（2）从日本海沟到我国东北,震源深度依次加深且几乎是从日本海沟沿直线倾斜下来,说明我国东北深震是日本海深震序列的一部分,同属于环太平洋地震带;（3）通过与东北深震区地球物理资料的对比,发现该区亚稳态橄榄石楔（Metastable Olivine Wedge,MOW）与深源地震的发生存在很好的相关性,由此推断东北深震的发生很可能是由橄榄石的相变引起的。 相似文献
12.
Reassessing the earthquake hazard in Kerala based on the historical and current seismicity 总被引：2，自引：0，他引：2
C.P. Rajendran Biju John K. Sreekumari Kusala Rajendran 《Journal of the Geological Society of India》2009,73(6):785-802
Given the lack of proper constraints in understanding earthquake mechanisms in the cratonic interiors and the general absence
of good quality database, here we reassess the seismic hazard in the province of Kerala, a part of the •stable continental
interior•, based on an improved historical and instrumental database. The temporal pattern of the current seismicity suggests
that >60% of the microtremors in Kerala occurs with a time lag after the peak rainfall, indicating that hydroseismicity may
be a plausible model to explain the low-level seismicity in this region. Further, an increment in overall seismicity rate
in the region in the recent years is explained as due to increased anthropogenic activities, which includes changes in hydrological
pathways as a consequence of rapid landscape changes. Our analyses of the historical database eliminate a few events that
are ascribed to this region; this exercise has also led to identification of a few events, not previously noted. The improved
historical database essentially suggests that the central midland region is more prone to seismic activity compared to other
parts of Kerala. This region appears to have generated larger number of significant earthquakes; the most prominent being
the multiple events (doublets) of 1856 and 1953, whose magnitudes are comparable to that of the 2000/2001 (central Kerala)
events. Occurrences of these historical events and the recent earthquakes, and the local geology indicative of pervasive faulting
as shown by widely distributed pseudotachylite veins suggest that the NNW-SSE trending faults in central midland Kerala may
host discrete potentially active sources that may be capable of generating light to moderate size earthquakes. The frequency
of earthquakes in central Kerala evident from the historical database requires that the seismic codes stipulated for this
region are made mandatory. 相似文献
13.
Loredana Bisio Rita Di Giovambattista Girolamo Milano Claudio Chiarabba 《Tectonophysics》2004,385(1-4):121-136
The Sannio-Matese region is one of the most seismically active regions of Italy and has been struck by large historical earthquakes. At present, the area is characterized by low magnitude background seismicity and small seismic sequences following M4 main events. In this paper, we show Vp and Vp/Vs models and 3D locations for a complete set of earthquakes occurring in the period 1991–2001. We observe a significant crustal heterogeneity, with large scale east-verging high Vp fault-related-folds, stacked by the Pliocene compression. The relocated earthquakes cluster along a 70° east-dipping, NW-striking plane located at the border of the high Vp thrust units. Normal fault earthquakes related to the young and active extension occur within these high Vp zones, interpreted as high strength material. We expect large future earthquakes to occur within these high Vp zones actually characterized by low magnitude seismicity at their borders. 相似文献
14.
V. Ribari
《Tectonophysics》1979,53(3-4)
Two earthquakes of March 26, 1511 with different positions of foci represent some of the strongest seismic phenomena which occurred in the past in the central part of Europe. In particular, both events were the beginning of an increasing seismic activity in this part of Europe, which was some centuries later again evidenced in a series of strong earthquakes in Friuli.Some characteristics of these shocks and the following aftershocks series show a pattern which is very similar to that of the Friuli earthquakes of 1976. However, the extent of the damage caused by the earthquakes in 1511 and the dimensions of the pleistoseistic region itself provide a basis for determination of some basic and only qualitative data about these shocks. 相似文献
15.
Water level fluctuations in twenty-one observation wells have been monitored for the last 10 years around the seismically active Koyna–Warna region, western India where earthquakes continue to occur even after four decades of the initiation of the seismic activity in the region. Fourteen of the observation wells act as volume strain meters as their water levels show earth tidal signals. Our analysis suggests three types of response of the well water levels to seismo-tectonic effects, i) one to local earthquakes, ii) to regional and teleseismic events, and iii) to local fluctuations in rock strain on regional scale. We observed five cases of co-seismic step-like well water level changes, of the order of few centimeters in amplitude, related to earthquakes in the magnitude range 4.3 ≤ M ≤ 5.2. All these earthquakes occurred within the network of wells drilled for the study and within 25 km distance of the recording wells. In three cases, drop in well levels preceded co-seismic step-like increases, which may be of premonitory nature. The second type of response is observed to be due to the passing of seismic waves from regional and teleseismic earthquakes like the M 7.7 Bhuj event on January 26, 2001 and the M 9.3 December 26, 2004 Sumatra earthquake. The third type is a well level anomaly of centimeter amplitude coherently occurring in several wells. The anomalies are similar in shape and last for several hours to days.From our studies we conclude that the wells in the network appear to respond to regional strain variations and transient changes due to distant earthquakes. The two factors which are important to co-seismic steps due to local earthquakes are the magnitude and epicentral distance. From the limited number of events we found that all local earthquakes exceeding M ≥ 4.3 have produced co-seismic changes. No such changes were observed for earthquakes below this magnitude threshold. 相似文献
16.
The relations between earthquakes and the eruption of mud volcanoes have been investigated at the Pede–Apennine margin of the Northern Apennines and in Sicily. Some of these volcanoes experienced eruptions or increased activity in connection with historical seismic events, showing a good correlation with established thresholds of hydrological response (liquefaction) to earthquakes. However, the majority of eruptions have been documented to be independent of seismic activity, being mud volcanoes often not activated even when the earthquakes were of suitable magnitude and the epicentre at the proper distance for the triggering. This behaviour suggests that paroxysmal activity of mud volcanoes depends upon the reaching of a specific critical state dictated by internal fluid pressure, and implies that the strain caused by the passage of seismic waves can activate only mud volcanoes in near-critical conditions (i.e., close to the eruption). Seismogenic faults, such as the Pede–Apennine thrust, often structurally control the fluid reservoirs of mud volcanoes, which are frequently located at the core of thrust-related folds. Such an intimate link enables mud volcanoes to represent features potentially suitable for recording perturbations associated with the past and ongoing tectonic activity of the controlling fault system. 相似文献
17.
Melt-origin pseudotachylytes are the most widely accepted feature recording earthquake slip in the fault rock record. However, reports of pseudotachylytes are rare compared to the frequency and distribution of earthquakes in active faults, suggesting melting occurs only under exceptional circumstances and therefore that pseudotachylytes are rarely formed. In this paper, we document the processes whereby pseudotachylytes are overprinted, destroyed and otherwise removed from the rock record. We present examples of recrystallized, altered, and cataclastically and crystal plastically deformed pseudotachylytes from a variety of ancient faults. Based on these observations, we identify characteristics of pseudotachylytes that are resistant to change over geologic time and develop criteria to allow recognition of relict pseudotachylytes. Our results imply that pseudotachylytes are vastly under-reported due to their vulnerability to destruction and the resulting difficulty in identification. As a consequence, the significance of frictional melting is underestimated. The criteria we propose to distinguish relict pseudotachylytes can help to reconcile the observed frequency of earthquakes with the difficulty of demonstrating ancient seismic slip in the rock record. 相似文献
18.
Fiona S. Tweed 《Geology Today》2012,28(6):217-223
Volcanic eruptions generate hazards, are potent agents of landscape change and have the power to alter global climate. Recent events in Iceland have emphasised the multi‐scale and trans‐boundary nature of hazards from ice‐volcano interactions and have highlighted their local, national and international impacts. Prompted by these recent events, this article reviews a selection of Icelandic volcanic eruptions in order to demonstrate the diversity of hazards and impacts generated by Icelandic volcanic activity. Some of the challenges associated with managing risks from Icelandic volcanic hazards are discussed and future prospects are outlined. 相似文献
19.
Rockfalls and debris avalanches triggered by earthquakes during the 2010–2011 Canterbury earthquake sequence killed five people and caused an estimated US$400 million in damages. In total, about 200 dwellings were directly impacted by some of the ~6000 rockfalls and debris avalanches that occurred across the Port Hills of Christchurch. This research presents the results of the analysis of a high-quality database of 61 individual rockfall impacts on 29 dwellings in the Port Hills of Christchurch, New Zealand. Dwellings in the Port Hills are typically simple timber-frame structures with wooden or unreinforced masonry cladding, comparable to most dwellings across New Zealand, North America, Australia, and elsewhere. Rockfall impacts on dwellings in this study were observed to follow a power law relationship between kinetic energy and (1) the runout distance into and through the dwelling and (2) the impacted area within the dwelling. The results have been quantified and are presented as a damage proportion, which is defined as the proportion of the area affected by an individual rock block inside the dwelling divided by the total area of the dwelling. These data provide a fundamental input for rockfall risk analysis and will allow the losses from rockfall impacts to be better constrained. 相似文献
20.
Avadh Ram 《Journal of Earth System Science》1981,90(2):189-195
About eighty earthquakes, exclusively from the Hindukush region, which were recorded at Gauribidanur seismic array (GBA) have been used in the present study. Short periodP-wave recordings upto 36 seconds were processed using adaptive cross-correlation filtering technique. The main objective of this exercise was to examine the signal complexities and seismic ray direction anomalies of these earthquakes which have identical epicentral distances and a narrow azimuthal range from GBA but different focal depths from 10 to 240 km. Slowness anomalies of the order of 1–4 sec/deg and azimuthal anomalies upto 6° have been found in this case. These deviations have been attributed to the upper mantle region between source and the receiver. Analysis of the data reveals that most of the events occurring at shallower depths had complex signatures as compared to the deeper events. The structure near the source region, complicated source functions and scattering confined to the crust-upper mantle near source are mainly responsible for complexity of the observed signals as the transmission path of the ray tubes from turning point to the recording stations is practically the same. 相似文献