Based on the recorded data obtained from macro survey points,survey intensity and strong motion instrument observation of the Ms7.0 Lushan earthquake in 2013,the instrument intensity values at each strong motion station were calculated by the strong motion monitoring technical team of Sichuan Earthquake Agency.The macro survey points were plotted on the isoseismal distribution map of the published survey intensity.The isoseismal distribution map of the instrument intensity was derived from the strong motion records and further calculated.We compared and analyed the relationship between the instrument intensity and the survey intensity of the M S 7.0 Lushan earthquake.The results show that:The instrument intensity and the survey intensity shows a good correspondence.The instrument intensity points of VI degrees are included in the area with the survey intensity of VI degrees,and the overall proportion reaches 88.24%.The instrument intensity points of Ⅶ degrees are included in the area above the survey intensity ofⅦ degrees,and the overall proportion reaches 81.82%.The regional scope and extent of the serious disasters caused by the earthquake can be well delineated by the contour range of the instrument intensity.The spatial distribution characteristics of the instrument intensity area are consistent with the control role of the seismogenic fault of the Ms7.0 Lushan earthquake.The attenuation of the intensity along the Longmenshan fault zone is slower than that in the vertical direction.The phenomenon is generally shown by the isoline area of the instrument intensity.The influence range of the hangingwall of the seismogenic fault is larger than that of the footwall,which is reflected by the isoline area of the instrument intensity.The control effect of the Ms7.0 Lushan seismogenic fault is also reflected in the spatial distribution map of the investigated intensity area.There are both correspondence and difference between instrument intensity distribution and survey intensity distribution.Considering that the earthquake disaster information in the disaster area might not be clear in a short time after the earthquake,the earthquake disaster situation in the disaster area can be quickly studied and judged after the earthquake.The possible earthquake disaster coverage,distribution of casualties,economic losses,lifeline engineering and other losses can be effectively estimated by local instrument intensity.The important basis of instrument intensity distribution is urgently and rapidly provided for emergency rescue decision-making,disaster relief plan formulation,disaster relief force deployment,and so on.

The M S 5.8,M S 6.0 and M S 5.2 Ma’erkang earthquakes occurred in Aba Tibetan and Qiang Prefecture,Sichuan on June 10,2022.Based on the sequence data of the M S 6.0 earthquake-swarm that occurred in 2022,the temporal and spatial characteristics of the earthquake-swarm sequence were studied in this paper.We used precise positioning of the earthquake-swarm sequence,combined with the results of the focal mechanism solution and regional tectonic data.The results show:The M S 6.0 Ma’erkang earthquake-swarm belongs to the earthquake-swarm triggered by multiple fault planes.The M S 6.0 Ma’erkang earthquake-swarm occurred in the Bayan Har active Block of level II,and spreads on the northwest side of the NW-trending Songgang fault and the two branches of the Songgang fault-Songgang fault 1 and 2 branches.The M S 5.8 and M S 6.0 earthquakes are the rupture events of the left-lateral strike-slip of the NNWtrending F A -and F B -faults on the northwest side of the Songgang fault.The M S 5.2 is the rupture event of the right-lateral strike-slip of the NE-trending Fc-fault,which may be“implicated"with the Longriba fault.The hypocenter of the M S 6.0 Ma’erkang earthquake-swarm are concentrated in the shallow part above 15 km.At the same time,several inspirations for obtaining the rapid research and judgment of post-earthquake trends are included:In the rapid trend study of the earthquake-swarms triggered by multiple fault planes,the tracking and judgment of fault seismogenic capacity,sequence distribution migration,sequence frequency and intensity in small areas all need to be focused.In the rapid study of sequence trends,it is necessary to pay attention to the understanding that the earthquake-swarm “sequence” is placed in the"seismogenic tectonic environment" and" historical rupture events".

1 研究背景 2022年6月10日在四川阿坝藏族羌族州马尔康市发生MS 6.0震群,其中6月10日00时03分09秒发生MS 5.8( ML 6.3)地震,相隔1 h 25 min 25 s发生MS 6.0( ML 6.5)地震,又相隔1 h 58 min 26 s发生MS 5.2( ML 5.6)地震.由此可见,在3.5小时内连续发生3次5级以上地震,多次震级相近地震的间隔时间相当短,给震群中每次较强地震发生后的趋势研判增加了难度.

1 研究背景 地震活动断层不同区段和时段均具有不同的力学特性,主要是表现在活动断层上发生地震的断层段所呈现的震前、同震、震后和震间4个时域范围内的滑动行为.换言之,地震活动断层的滑动行为分为震前、同震、震后和震间4个滑动阶段.通过研究活动断层地震破裂段震前、同震、震后和震间滑动,可深入破解沿活动断层破裂段的应力、应变的积累和释放的时空信息变化(Reilinger et al,1999;Yagi et al,2001;Ozawa et al,2004).

汶川8.0级地震后,我们收集分析了多位科研人员针对龙门山跨断层形变异常变化开展的多方研究,研究认识存在差异,分析认识上差异的原因主要还是没有将监测资料放入监测实际环境中去认识,而获得偏误认识;若将监测资料放入监测实际环境中去认识,才能获得符合实际的认识和合理的解释.

This work was based on integrated multidisciplinary data, including active tectonics, focal mechanism solutions, relocated small earthquakes, historical and modern seismicity, as well as GPS velocity fields. The authors have studied the Liupanshan fault zone (LPSFZ) in China, analyzing its tectonic-dynamic conditions and deformation style, cross-section structure, historical ruptures, GPS deformation, as well as modern micro-seismicity. Furthermore the authors discussed major earthquake hazard associated with the LPSFZ and one of its adjacent fault zones. The study suggests that the NNW-trending LPSFZ has been moving and deforming under the horizontal compression due to the resistance of the stable western part of the North China block, the Ordos block, to the eastward extrusive motion of the northeastern Tibetan block. Besides, lying at the right stepover or restraining bend between the NW-trending and left-lateral strike-slip Haiyuan and Longxian-Baoji fault zones, the LPSFZ absorbs and transforms the locally horizontal convergence of the two strike-slip fault zones. On the cross sections, the LPSFZ shows its characteristic as a large-scale reverse fault thrusting to the east, with a deep detachment zone at depth of 25 km. A seismic gap with a total length of 120 similar to 140 km exists along the middle-southern segment of the LPSFZ and the farther southeastern Longxian-Baoji fault zone (LXBJFZ), in which no M >= 61/2 events have occurred during the last similar to 1400 years at least. GPS deformation suggests that the two fault zones along the seismic gap have accumulated significant amount of elastic strain. Furthermore, that modern small earthquakes along several parts of the two fault zones are either sparsely distributed or absent also suggests that some fault patches are locked. In addition, an area with long-term low b-values is present along the middle-southern segment of the LPSFZ and the northernmost segment of the LXBJFZ, probably indicating high stress built up there. Therefore, the middle-southern segment of the LPSFZ and the LXBJFZ should be two fault sections that have high potential of major earthquakes in the future. The estimated maximum moment magnitudes for the potential events are M(w)7. 3 +/- and M(w)7.2 +/-, respectively.

川滇菱形地块东边界由鲜水河、安宁河-则木河以及小江断裂带组成, 其中, 鲜水河断裂带是川滇菱形地块和巴颜喀拉地块的边界, 而安宁河-则木河和小江断裂带是川滇菱形地块和稳定的华南地块的边界, 由于川滇菱形地块向南南东运动的整体性和较快速, 使得鲜水河、安宁河-则木河以及小江断裂带成为历史强震活动带.本文利用沿川滇菱形地块东边界的历史强震, 研究6.7级以上地震沿边界带的历史地震破裂特征.结果显示: 自1700年以来, 川滇菱形地块东边界历史上6.7级以上地震经历了4个活跃时期, 期间的最长平静时间是39年, 最短是29年, 而自1981年1月24日道孚发生6.9级地震以来, 至今(截至到2017年)已经平静了36年多, 接近历史最长平静时间, 表明川滇块体东边界新一轮强震破裂迁移活动即将开启.

利用南北地震带北段的区域GPS资料，结合区域的地震构造以及中小地震活动等信息进行分析，研究六盘山断裂带区域的地壳形变特征，探讨引起区域地壳形变的断裂带构造活动，并由此认识六盘山断裂带地震危险背景。

Several indexes about quality of Journal of Earthquake Research in Sichuan from 2001 to 2010 are analyzed briefly by using CNKI .The results show that the number of users in institutions has been increasing during 2001-2010 ,meanwhile the scope is sta-ble ,which suggests that readers of professional periodicals in seismology are researchers in specific institutions .The stable number of papers during the same period shows that paper source is limited to some specific research institutions .Moreover ,according to the statistical feedback information ,the main contribution of impact factor is from papers on technology innovation of monitoring instru-ment and technical management of seismic stations and secondary contributor is from papers on precursory observation analysis .The contributor of other kinds of papers is relatively smaller .The conclusion is that innovation type papers on observation technology of seismic stations are key factors of the quality of the journal .

<正>由于地貌和交通条件的限制,在跨龙门山断裂带区域只有短水准监测场地。多年持续监测的七盘沟和耿达场地跨龙门山后山断裂,灌县和双河场地跨龙门山前山断裂等4个短水准场地,而在龙门山中央断裂上没有监测场地。根据跨龙门山后山和前山断裂的4个短水准场地监测资料计算分析,在2008年5月12日汶川8.0级地震前,测量成果显示:龙门山后山断裂的近场速率为

The ground water level and temperature in the Sichuan area of Sichuan-Yunnan Block showed far-field response to the West Kunlun Mts.Pass MS8.1 earthquake on Nov.14,2001.We discuss the correlation between the regional tectonics in the Sichuan area and the seismogenic tectonic of the distant earthquake,and analyze the characteristics of the far-field response by zone and by stage.We think that the stages of seismogenic,coseismic and postseismic responses in the Sichuan area are just a far-field reflection of the whole process of the West Kunlun Mts.Pass MS8.1 earthquake from preparation to development and to occurrence.

A statistical analysis and discussion on intermediateterm anomaly items of earthquake precursors written in the annual report for the earthquake trend of Sichuan Province are made.The three historical steps are recalled.The characters of both monitoring and prediction of earthquake are summarized.The distance effective anomalies implied in the change processes of annual anomaly related to seismological and other subjects of earthquake precursors mentioned in the annual reports for the earthquake trend of Sichuan Province are discussed.

<正>努力提高地震科技期刊的学术质量,是科技期刊编辑努力追求的目标。一个期刊所刊载文章的学术质量是科技期刊价值的体现,而学术质量又取决于它所拥有的原创文稿的价值,文稿的价值反映在学术价值、研究价

Based on the data of the historical seismicity,seismogeology,earthquake mechanism and seismic series analyses,we think that the Yuanyan M5.8 Earthquake on 24 May 2001 resulted from the Ninglan M6.2 Earthquake on 19 November 1998.Two earthquakes belong to the same seismic series which last about 58.6 months.The Yuanyan M5.8 Earthquake belongs to the main shock-after shock type.After the Yuanyan M5.8 Earthquake,there are 1409 earthquakes which the seismic magnitudes are equal to or greater than 0.0 on the Richter scale.Among them there are 6 earthquakes which the seismic magnitudes are between 4.0 and 4.9 and the maximum magnitude of after-shocks is 4.7 on Richter scale.The predominance spacial distribution direction of earthquakes is a north-north-east and south-south-west trending.It is coincident with the both seismic intensity line and the nodal plane.So we think that the Yuanyan M5.8 Earthquake on 24 May 2001 is caused by the movement of the south-north faults.

We divide Southwest China area into 5 research sub-areas and then analyze the space-temporal characteristics on the precursory earthquake swarms and the prominence earthquakes before a strong earthquake.In 5 areas in Southwest China the characteristics of precursory earthquake swarms and prominence earthquakes in every are alike but at the same times are different according to every areas.From the common characters,5 predicting areas in Southwest China after a precursory earthquake swarm and a prominence earthqauake occureed for 1 to 2 years,a strong earthquake may occur and the epicenter may be located at the location of the precursory earthquakes or the relative falut belts.Sichuan and Yunnan fault block tectonics are complex.Before a strong earthquake there is a precusory earthquake swarm or a prominence earthquake.In another words,in 5 predictive areas the precursory earthquake swarm and the prominence earthquake are relative to a strong earthquake and are relative to the seismological geological structures of Southwest China.

To find if there is any difference between the simulated and digital observation data of extensometer in Panzhihua Seismic Station, we use 3 - th polynomial to fit observation data in a least squares sense. The fitting result parameter p is a row vector of length n+ 1 containing the polynomial coefficients. The p0, p1, p2 and p3 parameters can express the long- term drift, linear, parabola and 3 - th changes respectively in the observation data. So we use these parameters to discuss the differences in two kinds of data. Our comparison results show that two kinds of data have no any differences in long- term and parabola changes but change exists in 3 - th curve. In another words, there are some differences in high order irregular changes in observation data. So the digital observation data includes more information about high order irregular changes than simulated observation data. Our results can be of help for further study of two kinds of data.

According to the present block structures,the active intensities of faults,the active characteristics of historical earthquakes and the interacting effect between blocks in southwestern China,we divide the seismicity region of southwestern China into 5 sub-blocks,which include Sichuan Qinghai block,Western Sichuan block,Central Yunnan block,Western Yunnan block and Southeastern Sichuan block.We summarize the characteristics of both present and historical seismicities of strong earthquakes in sub geological structure and divide the prediction region of medium-strong earthquakes into 5 intensive researching areas in order to predict earthquake to happen in these areas.

In this paper, the some observations of ground water in Sichuan and Yunnan are selected from many observation means. The station distribution of observations of ground water is relatively uniform. Moderate-high frequency information had been obtained from these observation data. The field of the moderate-high frequency information is created with the method of power function attenuation. The short-imminent comprehensive precursory field is researched with the observation data that have same physics significance. It shows that the seesaw variety of the comprehensive precursory field is big range in the area near the focal zone where any earthquakes will occur. The teams of moderate-high frequency information are selected from the some observations. The change course of the short-imminent comprehensive precursory with time is researched also. It shows that the short-imminent comprehensive precursory of moderate-high frequency information increase clearly in three months before any earthquake. It gives prominence to the comprehensive precursory information of the observation.

采用四川省地震局地震台网自1970年运行以来的地震记录资料,根据区域地震活动的分布信息并结合已有的活动断裂考察资料来进一步划分地震活动的区域,将四川及邻区地震活动区划分为9个小区域.在划分的9个区域中,除东部盆地地震活动区地震活动较弱外,其余区域均有历史强震记录,显示出整个区域的地震活动东弱西强的特点.从地震活动的频次指标也可以看出,呈现沿主干断裂的地震频次略高 ,总体也呈现出地震频次东部低西部高的特点.各个小区域的地震活动频次显示出波浪起伏的特点.在各小区域内强震发生前3个月左右的短、临阶段,小区域内地震能量均明显出现加速释放共性特征.同时,出现相邻区域的地震频度和强度相应减弱、地震空间分布的集中度同步减弱及能量释放趋于减弱的协同性特征.