6600 years of earthquake record in the Julian Alps (Lake Bohinj,Slovenia)

Sequences of lake sediments often form long and continuous records that may be sensitive recorders of seismic shaking. A multi‐proxy analysis of Lake Bohinj sediments associated with a well‐constrained chronology was conducted to reconstruct Holocene seismic activity in the Julian Alps (Slovenia). A seismic reflection survey and sedimentological analyses identified 29 homogenite‐type deposits related to mass‐wasting deposits. The most recent homogenites can be linked to historical regional earthquakes (i.e. 1348 ad , 1511 ad and 1690 ad ) with strong epicentral intensity [greater than ‘damaging’ (VIII ) on the Medvedev–Sponheuer–Karnik scale]. The correlation between the historical earthquake data set and the homogenites identified in a core isolated from local stream inputs, allows interpretation of all similar deposits as earthquake related. This work extends the earthquake chronicle of the last 6600 years in this area with a total of 29 events recorded. The early Holocene sedimentary record is disturbed by a seismic event (6617 ± 94 cal yr bp ) that reworked previously deposited sediment and led to a thick sediment deposit identified in the seismic survey. The period between 3500 cal yr bp and 2000 cal yr bp is characterized by a major destabilization in the watershed by human activities that led to increases in erosion and sedimentation rates. This change increased the lake's sensitivity to recording an earthquake (earthquake‐sensitivity threshold index) with the occurrence of 72 turbidite‐type deposits over this period. The high turbidite frequency identified could be the consequence of this change in lake earthquake sensitivity and thus these turbidites could be triggered by earthquake shaking, as other origins are discarded. This study illustrates why it is not acceptable to propose a return period for seismic activity recorded in lake sediment if the sedimentation rate varies significantly.     

Process of Housing Damage Assessment: The 1995 Hanshin-Awaji Earthquake Disaster Case

Rebuilding of victims' livelihoods was a crucial issue in the restoration process in the1995 Hanshin-Awaji Earthquake Disaster. Housing damage assessment influencedmost of the rebuilding of the livelihood in the long term, because the Victim Certificatesissued by the local governments based on the results of the Housing damage assessmentwas required to receive most of the individual assistance measures. In the process ofHousing damage assessment, many complex problems arose, leading to extensivework on the part of the disaster responders. Consequently, a considerable number ofvictims were dissatisfied with the assessment and applied for a resurvey. Due to a floodof requests for resurvey, disaster responders had to work on damage assessment, leavingrelief activities aside.In order to facilitate Housing damage assessment, this paper discusses thefollowing five points: (1) the processes and the problems of assessments performedin the Hanshin-Awaji Earthquake Disaster, (2) the changes in the nature of informationneeded by the victims, (3) the improvements over the present damage assessment, (4)the housing situation in Japan, and (5) the international situation on damage assessment.It is obvious from the results that a poor damage assessment system and the size ofthe disaster produced a very large work load. Differences in appreciation among theinvestigators also contributed to unfair assessments and led to the victims beingincreasingly dissatisfied by the survey results. Finally, a design concept for acomprehensive damage assessment system, which has been derived from theabove five points, is proposed for post-disaster management.     

城市化防震减灾经济性研究

本文通过对东南沿海地震背景和地震破坏性经济损失,结合国内外城市化进程中防震减灾经济性对比研究,认为地震破坏的负面效应所带来的经济损失十分巨大。因而必须加强防震减灾工作为保障城市化顺利发展服务。     

A robust satellite technique for monitoring seismically active areas: The case of Bhuj–Gujarat earthquake

A robust satellite data analysis technique (RAT) has been recently proposed as a suitable tool for satellite TIR surveys in seismically active regions and already successfully tested in different cases of earthquakes (both high and medium–low magnitudes).In this paper, the efficiency and the potentialities of the RAT technique have been tested even when it is applied to a wide area with extremely variable topography, land coverage and climatic characteristics (the whole Indian subcontinent). Bhuj–Gujarat's earthquake (occurred on 26th January 2001, M_S  7.9) has been considered as a test case in the validation phase, while a relatively unperturbed period (no earthquakes with M_S ≥ 5, in the same region and in the same period) has been analyzed for confutation purposes. To this aim, 6 years of Meteosat-5 TIR observations have been processed for the characterization of the TIR signal behaviour at each specific observation time and location.The anomalous TIR values, detected by RAT, have been evaluated in terms of time–space persistence in order to establish the existence of actually significant anomalous transients. The results indicate that the studied area was affected by significant positive thermal anomalies which were identified, at different intensity levels, not far from the Gujarat coast (since 15th January, but with a clearer evidence on 22nd January) and near the epicentral area (mainly on 21st January). On 25th January (1 day before Gujarat's earthquake) significant TIR anomalies appear on the Northern Indian subcontinent, showing a remarkable coincidence with the principal tectonic lineaments of the region (thrust Himalayan boundary).On the other hand, the results of the confutation analysis indicate that no meaningful TIR anomalies appear in the absence of seismic events with M_S ≥ 5.     

Holocene beach deposits for assessing coastal uplift of the northeastern Boso Peninsula, Pacific coast of Japan

This paper presents a case study that assessed spatial variations in the tectonic uplift rates of beach deposits in the relict Kujukuri strand plain, situated on the northeastern coast of the Boso Peninsula, eastern Japan. The southern Boso Peninsula is tilted downward to the northeast due to plate subduction along the Sagami Trough. However, the cause of the northeastern coast uplift creating the relict strand plain is unclear, due to the absence of a Holocene raised marine terrace sequence. Elevations and ages of beach deposits were collected from drilled cores and ground-penetrating radar profiles along three shore-normal sections in the southern Kujukuri strand plain. From this, alongshore variations in the relative sea level since the mid-Holocene could be seen. These corresponded to north-to-northeast downward tilting at a rate of 0.4 m/ka for an interval 10 km and are concordant with the longer term tilting of the last interglacial marine terrace surrounding the plain. Although it is difficult to assess shore-normal variations of uplift based on the present dataset, the recognized tilting apparently continues to the tilting of the southern Boso Peninsula, implying the Sagami Trough probably affects the uplift of the Kujukuri coast.     

5.12汶川地震对都汶公路(G213)沿线土地破坏及损失评价

5.12汶川地震及其次生山地灾害对灾区的土地资源造成了严重破坏,损失巨大.以重灾区都汶公路沿线为研究对象,通过野外实际调查,利用遥感影像解译和土地利用资料,探讨了地震引起的崩塌、滑坡等次生山地灾害对土地利用的破坏方式和特征,次生山地灾害以移动破坏、淤埋破坏和拉裂破坏3种形式破坏土地资源,并对土地利用损失进行了评估.结果表明:①各种土地利用类型中,淤埋破坏是最主要的破坏形式,占总破坏面积的77.23%,移动破坏面积占总破坏面积的22.77%;②林地和草地破坏呈现出在缓坡地带和陡坡地带破坏比例高,在中间地带破坏比例低的规律,旱地破坏具有随着坡度的增大而加剧的趋势;③研究区内各类土地利用类型总损失价值达76 577.26万元,其中林地损失量最大,占总损失价值的87.18%,是地震引起崩塌、滑坡灾害损失的主要对象.     

SOURCE RADIATION AND RESPONSES OF WAVE PROPAGATION

Recordings of seismic waves propagating from earthquake source to a station at the earth's surface are a system response function.The convolution operator in time domain can be simplified as a multiplication operator in frequency domain.We discuss in frequency domain the separation of source,path and site effects for global scaling of earthquake source radiation.Also discussed are source scaling model,faulting mechanism,and the H/V inversion problems with crustal and near surface structures.Gross features of apparent source spectra appear to be not much region-dependent although there may be difference between tectonic styles within a region of tectonic mixture for which we need further study as data accumulate.Vertical spectra may be a better approach to approximate source radiation,as it has less crustal amplification effects than horizontal spectra.The H/V ratio is evidently a comprehensive indicator of amplification effects from near surface to deep structure.This gives it potential as an inversion tool to deduce site crustal structure.     

福州、小陶地震速报技术研究

本文通过分析福州、小陶地震的波形记录及各种定位参数 ,总结了该地区的震相特征和各台的震级情况 ,结合地震速报的规程 ,提出了对这两个地区地震速报的建议。     

5.12汶川地震对黄龙世界遗产地源泉水文地球化学的影响——高分辨率和高精度的水文地球化学监测证据

2008年5月12日的汶川特大地震不仅造成了惨重的人员伤亡和巨大的经济损失,而且对当地生态环境产生了严重的影响。本文根据黄龙钙华景观退化的人为和自然影响机理研究获得的部分高分辨率和高精度水文地球化学监测数据分析发现,大地震通过诱导控制黄龙源泉的深源断裂活动对源泉的水文地球化学产生了显著影响,主要表现为地震后泉流量、水温、电导率和CO2分压升高,反映出地震增加了地下向地表的水、热、钙离子和CO2通量。然而,地震对从泉水中沉积的钙华景观的后续影响以及汶川地震造成深源CO2向大气CO2释放对全球碳循环的影响,有待进一步的监测评估。      

Behaviour of a rupture of the 21 June 2000 earthquake in South Iceland as revealed in an asphalted car park

A major earthquake (M=6.6) occurred on 21 June 2000, in South Iceland. This paper presents an unusual example of left-lateral strike-slip displacement recorded in a newly asphalted car park surface through a mechanically consistent pattern of open fissures and pressure ridges resulting from simple shear and rotation. Measurement of these features allows accurate reconstruction of the local deformation. The behaviour of the asphalt layer resembles that of analogue physical models, especially in terms of rotations induced by shear deformation. It is finally shown that through a wide range of scales some basic patterns associating rotation and opposite senses of strike-slip exist in the South Iceland Seismic Zone.