岷江断裂南段与1933年叠溪地震研究

１９３３年叠溪７．５级地震是发生在青同原东南缘的重大事件。对这次地震的等烈度线形态及与之相关的发震构造的认识有着明显的分歧。本文基于野外新发现的南北向活动断裂以及叠溪地震地面破裂的研究,认为这次地震的发震构造可能是作为岷江断裂南延部分的南北向活动断裂。     

利用精定位小震资料反演1933年叠溪M7?地震震源断层面参数

1933年叠溪发生7?级强震,关于此次地震的发震构造存在较大争议,有些学者认为NW向松坪沟断裂是此次地震的发震构造,另有学者认为近NS向岷江断裂南段才是这次地震的发震构造。本文根据成丛小震发生在大震断层面附近的原则,利用1990-2014年精定位小震目录,根据万永革等（2008）提出的震源断层面拟合方法,反演了叠溪地震震源断层走向、倾角和位置。断层走向和倾角分别是172.8°和82.9°,倾向偏向西。本文结果更支持岷江断裂南段为叠溪地震发震构造这一结论。     

关于1933年叠溪7.5级地震若干问题的讨论

１９３３ 年叠溪７５ 级地震是本世纪发生于青藏高原东缘的重大事件。对这次地震, 不同部门曾进行考察, 但给出的等烈度线图有着明显的分歧, 这一分歧意味着对该次地震发震构造认识的不同。本文基于对该次地震的震害特征、震中位置、震中区地质构造环境以及发震构造的讨论, 认为南北向的活动断裂有可能是该次地震的发震构造, 而该活动断裂可能是岷江断裂的南延。     

1933年叠溪地震的发震位置、震源机制与区域构造

1933年发生于中国四川省境内的叠溪M7.5大地震造成了人民生命财产的重大损失.然而限于资料匮乏,人们对此次地震的发震构造和震源机制解的认识尚不统一.本文收集整理了当时全球各地震台站对此次大地震的记录,对叠溪地震进行了重新定位,确定的震中位置为31.9°N,103.6°E.挑选具有P波初动符号的台站记录,利用格点尝试法...     

上海徐家汇观象台记录的1933年四川叠溪地震参数计算

地震学者对1933年叠溪大地震进行了大量研究,由于资料匮乏,学术界至今对该地震的震源位置、震级、发震时间3要素有不同看法。本文利用上海徐家汇观象台1933年四川叠溪大地震三分向记录,通过对叠溪地震事件图纸的重新分析校核,利用IASP91全球走时模型对发震时间、震中距和震级3要素重新行计算和反演,得出的定位结果为：发震时刻为1933年8月25日7时50分15秒、震中距为16.25°、震级为MS7.49。该结果和其他研究学者在发震时刻和震中距上偏差较大,发震时刻相差17 s,震中距相差1°左右,两者偏差较大,究其原因是采用的方法不同,前人是基于宏观资料、现场调查以及后续小震反演得到的结果。     

周晓和先生留存的1933年四川叠溪地震照片简介

1933年8月25日四川省茂县叠溪发生7 1/2 级强烈地震。这次地震造成了大量的滑坡与崩塌,叠溪镇全城被毁,伤亡惨重。震后45天地震堰塞湖溃决,又造成严重的次生水灾。当年12月,地质学家周晓和先生曾带领四川大学师生赴震区考察,他们拍摄和收集了许多照片,其中一些留存至今。文中简要介绍了新近发现的周晓和先生留存的有关叠溪地震的4张照片,包括四川大学地质考察团的合影、叠溪城陷落后的情景、被水灾冲毁的索桥与古亭,以及叠溪地震的灾民。这些珍贵照片提供了叠溪地震的直观信息。     

关于1 933年叠溪7.5级地震若干问题的讨论

１９３３年叠溪７．５级地震是本世纪发生于青藏高原东缘的重大事件。对这次地震,不同部门曾进行考察,但给出的等烈度线图有着明显的分歧。这一分歧意味着对该次地震构造认识的不同。本文基于对该次地震的震害特征、震中位置,震中区地质构造环境以及发震构造的讨论,认为南北向的活动断裂有可能是该次地震的发震构造,而该活动断裂可能是岷江断裂的南延。     

发震构造呈复杂空间关系下相互影响发震的机理研究——以汶川地震为例

对发震构造呈复杂几何关系(发震构造在平面投影呈非平行关系)下彼此发震影响的机理进行了研究.从发震的“垂震底继”影响关系研究了1933年迭溪地震M7.5和1976年松潘Ms7.2地震对后来发生汶川M8地震的龙门山地震构造的孕震能量叠加的加震作用;同时也指出汶川8级地震对周边断裂的减震作用,计算并指出了其影响减震的距离.研究对CPSHA中对发震构造呈复杂几何关系时,如何确定地震带内各潜在的震源空间分布函数fi,mj提供了大震加减震的判断理论依据.还讨论了汶川地震孕震模式的更复杂性,针对某些用巴颜喀拉块体向东南方向移动挤压龙门山孕震构造,进而解释汶川地震的逆冲性所带来的矛盾的观点,对其孕震的复杂性提出了问题所在和初步探讨.     

1584年肇庆5.0级双震的发震构造讨论

1584年肇庆两次5.0级地震属于双震。两次地震等烈度线长轴均呈北西向。震中附近有两条较大的断裂，一是北东向高要断裂，它是吴川－四会断裂的分支断裂，并控制了一系列地震分布，可谓之控震构造。另一条是北西向白土断裂，与两次地震等烈度线长轴一致，联系到1905年43／4级地震也发生在此断裂附近，该断裂应是本次地震发震构造。     

Re-discussion on the Jiaochang Arcuate Structure, Sichuan Province, and the Seismogenic Structure for Diexi Earthquake in 1933

The Jiaochang arcuate structure is one of the numerous arcuate structural belts in Sichuan. The present paper gives a further argument about the characteristics of that arcuate structure and the new activity of the Songpinggou fault and affirms that the Songpinggou fault is an active fault in the Holocene epoch. The Diexi M7.5 earthquake took place in 1933 on the west wing of that arcuate structure, near the apex of the arc. Many authors have given quite different opinions about the genetic structure of that earthquake. The authors have made on-the-spot investigations time and again over recent years. Besides this, the authors have also further studied the shape of intensity contour lines, the distribution characteristics of ground surface seismic hazards, the left-lateral dislocation of buildings along the Songpinggou fault, the NWtrending ground fissures that developed on the ground surface after earthquake, and so on. On this basis, it is still considered that the seismogenic fault of the 1933 Diexi M7.5 earthquake was the Songpinggou fault on the west wing of the Jiaochang arcuate structure.     

Re-discussion on the Jiaochang Arcuate Structure, Sichuan Province, and the Seismogenic Structure for Diexi Earthquake in 19331

The Jiaocbang arcuate structure is one of the numerous arcuate structural belts in Sichuan. The present paper gives a further argument about the characteristics of that arcuate structure and the new activity of the Songpinggou fault and affirms that the Songpinggou fault is an active fault in the Holocene epoch. The Diexi M7.5 earthquake took place in 1933 on the west wing of that arcuate structure, near the apex of the arc. Many authors have given quite different opinions about the genetic structure of that earthquake. The authors have made on-the-spot investigations time and again over recent years. Besides this, the authors have also further studied the shape of intensity contour lines, the distribution characteristics of ground surface seismic hazards, the left-lateral dislocation of buildings along the Songpinggou fault, the NWtrending ground fissures that developed on the ground surface after earthquake, and so on. On this basis, it is still considered that the seismogenic fault of the 1933 Diexi M7.5 earthquake was the Songpinggou fault on the west wing of the Jiaochang arcuate structure.     

South Segment of Minjiang Fault and Diexi Earthquake in 1933

Diexi earthquake(M7.5)in 1933 is a great event that occurred at the east border of Qinghai- Xizang Plateau in the 20th century.There are obviously different opinions about the shape ofisoseismal lines and the genetic fault of this earthquke.Based on the study of the newlyfound north-south trending active fault and ground fissures of Diexi earthquake,this papertends to hold that,as the southward extension of Miujiang fault,this north-south trendingactive fault might be the genetic fault of this event.     

Seismogenic tectonics of the Qian-Gorlos earthquake in Jilin Province,China

The Qian-Gorlos earthquake, which occurred in the Songliao basin in Jilin Province in 1119 AD, was the largest earthquake to occur in NE China before the 1975 Haicheng earthquake. Based on historical records and surface geological investigations, it has been suggested previously that the earthquake epicenter was in the Longkeng area. However, other workers have considered the epicenter to be in the Halamaodu area based on the landslides and faults found in this region. No seismogenic structure has yet been found in either of these two regions. We tried to detect active faults in the urban areas of Songyuan City, where the historical earthquake was probably located. One of the aims of this work was to clarify the seismogenic structure so that the seismic risk in the city could be more accurately evaluated. The area was investigated and analyzed using information from remote sensing and topographic surveys, seismic data from petroleum exploration, shallow seismic profiles, exploratory geological trenches on fault outcrops, and borehole data. The geophysical data did not reveal any evidence of faults cutting through Cretaceous or later strata under the Longkeng scarp, which has been suggested to be structural evidence of the Qian-Gorlos earthquake. The continuous fault surfaces on the back edge of terraces in the Halamaodu area stretch for >3.5 km and were probably formed by tectonic activity. However, results from shallow seismic profiles showed that the faults did not extend downward, with the corresponding deep structure being identified as a gentle kink band. A new reverse fault was found to the west of the two suggested epicenters, which presented as a curvilinear fault extending to the west, and was formed by two groups of NE- and NW-trending faults intersecting the Gudian fault. Three-dimensional seismic and shallow seismic data from petroleum exploration revealed its distinct spatial distribution and showed that the fault may cut through Late Quaternary strata. Exploration boreholes and later geomorphological studies provided further proof of this. Based on these results and analysis, the Gudian fault was confirmed as having been an active fault since the Late Quaternary, with the possibility of earthquakes of magnitude >7 in the future. The Qian-Gorlos earthquake was most probably the result of breakage on one or two sections of this 66-km-long fault.     

10余年来甘肃省中强地震的发震构造特征

归纳总结了1995年以来甘肃省所发生的9次Ms5．0以上破坏性地震的发震构造特征，综合分析了其共性和个性特点。结果表明：所发生的中强破坏性地震大多位于活动性较弱的次级活动断裂带上或主干活动断裂带边缘，其分布具有时间上的分段性、空间上的分区性和迁移性特点，并具有从山前向盆地内部扩展的发展趋势。     

阳江MS4.9级地震影响场与发震构造关系讨论

2004年9月17日02时31分广东省阳江市发生MS 4.9级地震,造成14个镇的57个行政村共1620多间房屋(主要为老旧民房)遭受轻微破坏,受影响居民21195户,经济损失2300多万元。震后进行了地震影响场调查,绘制了这次地震的等震线分布图,并对其发震构造进行了分析探讨。     

对1556年84/级大地震震中位置和发震构造的新认识

郭增建先生 (195 7)称 15 5 6年 8 级大地震为关中大地震 ,并绘制了等震线图。 1983年版中国地震目录将其称为华县地震。之后 ,中国地震目录几经修改 ,但对震中位置都没再进行过进一步的研究和修订。 80年代以来 ,几位研究者从不同角度渐次提出这次地震的震中位置不在华县的新见解。本文同意这些见解 ,并通过分析大量史料和对发震构造的研究作进一步论证 ,提出对这次地震震中位置和发震构造的新认识。(1) 15 5 6年 8 级大地震的震中位置不在华县。极震区分布在蒲州 (今永济西黄河东岸 )、朝邑、潼关卫、华阴、华州、解州一带 ,故震中位置宜定在蒲州、潼关卫、华阴、朝邑之间 ,即北纬34°4 4′ ,东经 110°16′ ,震级仍沿用 1995年版中国地震目录修订的 8 级。由于蒲州最重 ,可称为15 5 6年蒲州 8 级大地震。(2 ) 15 5 6年 8 级大地震的发震构造不只是华山山前断裂 ,而是大致沿黄河分布的北北东向右旋走滑断裂带及其南北两端相反方向分布的渭河拉分盆地和运城、临猗一带张性地堑、地垒带 ,由它们共同组合而成的走滑型发震构造带 ,为该次大地震的发震构造。     

1306年宁夏固原地震考证与发震构造探讨

根据历史地震资料重新考证和野外实地调查结果,圈定的1306年宁夏固原地震重破坏区(Ⅷ度区)位于固原、开城和朝那一带,极震区(Ⅸ～X度)位于固原开城附近,其震级达7级左右.地震重破坏区长轴方向为NNW向,大致与该区六盘山东麓断裂的固原—和尚铺段相吻合,该段断裂为全新世活动的左旋逆冲断裂,局部段残存有类似地震破裂带遗迹,推测与本次地震有关.