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滑动速率是研究断裂运动学特征、地震活动性和区域应变分配的重要参数和依据。前人关于甘孜-玉树断裂带滑动速率的研究结果存在较大差异，因此，其晚第四纪滑动速率有待进一步调查研究。本文基于卫星影像解译和野外实地考察，对甘孜-玉树断裂带西段（玉树断裂）上典型断错地貌点进行测量分析，得到玉树断裂晚第四纪走滑速率为6.6±0.1-7.4±1.2mm/a。通过与前人对甘孜-玉树断裂带东段（甘孜断裂）滑动速率的研究结果进行对比，发现甘孜-玉树断裂带东、西段滑动速率不一致，其原因是甘孜断裂的左旋滑移在向西传递的过程中，一部分应变被分配到了巴塘盆地南缘断裂上。巴塘盆地南缘断裂的存在很好地解释了玉树断裂的走滑速率比甘孜断裂偏低的原因。但是，从区域变形来看，巴塘盆地南缘断裂分配的滑动速率恰好说明了甘孜-玉树断裂带东、西段及鲜水河断裂带的水平构造变形是协调一致的。 相似文献
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通过分析阿尔金断裂带西段车尔臣河出山口以西 85°～ 86°E的高精度SPOT卫星影像 ,结合野外考察和年代学研究 ,对阿尔金断裂带西段 3个典型走滑断层的断错地貌进行了研究。在库拉木拉克 ,阿尔金断裂带西段自 (6 0 2± 0 4 7)kaBP以来的左旋滑动速率为 (11 6± 2 6 )mm/a ,自 (15 6 7± 1 19)kaBP以来的左旋滑动速率为 (9 6± 2 6 )mm/a ;阿羌牧场附近 ,自 (2 0 6± 0 16 )kaBP以来的左旋滑动速率为 (12 1± 1 9)mm/a ;达拉库岸萨依附近 ,自 (4 91± 0 39)kaBP以来的左旋滑动速率为(12 2± 3 0 )mm/a。由此得到阿尔金断裂带全新世以来的平均滑动速率约为 (11 4± 2 5 )mm/a。以阿尔金断裂带走向N75°E计算 ,阿尔金断裂带西段左旋走滑所吸收的青藏高原SN向缩短速率为 (3 0±0 6 )mm/a 相似文献
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祁连山活动断裂带中东段冷龙岭断裂滑动速率的精确厘定 总被引：14，自引：0，他引：14
冷龙岭活动断裂是青藏高原东北缘祁连山断裂带的重要组成部分, 位于祁连山断裂带中东段。 根据野外考察结果认为, 该断裂全新世以来活动强烈, 主要表现为左旋走滑运动, 并伴有正倾滑性质, 断错地貌特征明显。 通过高分辨率SPOT卫星数字影像和大比例尺航空照片处理确定断层的位置, 利用断错地貌测图、 热释光(TL)和碳十四(14C)测年方法, 厘定了冷龙岭断裂的晚第四纪滑动速率, 冷龙岭断裂晚更新世以来的平均水平滑动速率为(4.3±0.7)mm/a, 全新世晚期以来的平均水平滑动速率为(3.9±0.36)mm/a。 相似文献
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基于卫星影像解译和野外考察测量,本文对东昆仑断裂带中东部的3条次级断裂(托索湖断裂、玛沁断裂和玛曲断裂)的滑动速率以及全新世以来的古地震活动特征进行了分析研究。托索湖段与玛沁段走向产生20°和30°的双挤压弯曲,形成阿尼玛卿山挤压隆起,作为托索湖段和玛沁段的破裂分段标志,成为1937年托索湖7.5级地震地表破裂带的终止点;在西贡周西侧和莫哈塘南侧,阿万仓断裂以40°的夹角与东昆仑断裂带相交,形成西贡周断裂交汇区,成为玛沁段与玛曲段破裂分段的标志。通过构造地貌方法获得西段托索湖断裂晚第四纪晚期以来的平均水平速率为10.8±1mm/a,垂直滑动速率为1.2±0.2mm/a;中段玛沁断裂带晚第四纪晚期以来的平均水平滑动速率为9.3±2mm/a,垂直滑动速率为0.7±0.1mm/a;西贡周断层交汇区平均水平滑动速率为7.4±1mm/a,垂直滑动速率为1.2±0.1mm/a;东段玛曲断裂晚第四纪晚期以来的平均水平滑动速率为4.9±1.3mm/a,垂直滑动速率为0.3mm/a。断裂的滑动速率从西至东呈梯度下降,通过构造转换矢量分解获得阿万仓断裂西支的左旋水平走滑速率为2.4mm/a,东支的左旋水平走滑速率为1.4mm/a,垂直断裂的水平缩短速率为2.3mm/a,阿万仓断裂带西支和东支构成一个滑动分解模式。3条次级断裂的活动均产生独立地表破裂,西侧的托索湖断裂发生了1937年MS7.5级地震,中段玛沁断裂发生了公元1061年格萨尔王时期和距今358~430CalaBP的地表破裂,玛曲段地表破裂距今约1055~1524aBP,显示出段落之间应力触发有关的地震破裂事件沿断裂带单向迁移的特征。同时利用断裂单次地震位移和古地震复发周期获得断裂的长期滑动速率,结果显示与构造地貌方法获得的滑动速率几乎一致,也显示自西向东逐渐递减的趋势。断裂滑动速率的递减与几何结构走向的弯曲以及横向断裂的相交一一对应,东昆仑断裂带的滑动速率梯度递减的主要原因是东昆仑断裂带东延和横向断裂相交,构造转换造成的。 相似文献
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《地震地质》2016,(1)
文中从几何结构特征、断裂长期滑动速率和古地震复发特征3个方面对阿万仓断裂进行了研究。详细的遥感解译和野外调查结果表明:1)阿万仓断裂作为东昆仑断裂带东段(玛沁—玛曲段)的分支断裂,和东昆仑断裂一样也是1条全新世活动断裂,性质为左旋走滑兼逆断,总长约200km。西北段由2条总体走向310°,相距约16km近平行的次级断层组成,向SE方向合为1条断裂。2)在阿万仓断裂上发现大约15km长的古地震地表破裂带,表现为断层陡坎、断塞塘、地裂缝、断层沟槽等典型断错微地貌现象。3)经航、卫片解译,野外现场调查,断错地貌测量和样品测试,得到该断裂晚第四纪以来的平均左旋水平滑动速率为3mm/a,垂直滑动速率约0.07mm/a。4)通过对断错最新地貌面的测年和探槽剖面分析,认为阿万仓断裂带存在4次古地震事件,属原地复发型,最新1次事件是在(850±30)a BP以后发生的。5)阿万仓断裂左旋滑动速率与东昆仑断裂带玛沁—玛曲段递减的滑动速率量值相当,它的存在和发现可以很好地解释东昆仑断裂带东段(玛沁—玛曲段)滑动速率递减的特征。东昆仑活动断裂带中东段滑动速率逐渐递减,与东昆仑活动断裂带中东段帚状散开的几何结构有关,其中的阿万仓断裂是东昆仑断裂带东延过程中的重要分支断裂,吸收了东昆仑断裂带东延的应变分配。 相似文献
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川西理塘断裂带平均滑动速率、地震破裂分段与复发特征 总被引：8，自引：0，他引：8
理塘断裂带是川西北次级块体内部的一条活动断裂带.野外调查获得其晚第四纪断错、近代地震破裂、破裂分段的新证据, 估算出断裂的滑动速率、特征地震震级与复发间隔.结果表明, 理塘断裂带由毛垭坝盆地北缘、理塘和康嘎-德巫等三条次级断裂组成, 以左旋走滑为主, 不同部位伴有不等的逆倾滑分量. 由7个地点的断错地貌及相关沉积物年龄估算断裂带距今约14 ka以来的平均左旋滑动速率为4.0±1.0 mm/a, 垂直(逆)滑动速率0.1~1.8 mm/a; 三条次级断裂均为独立的地震破裂段, 相应特征地震最大矩震级估值为7.0~7.3, 平均复发间隔为500~1000年, 北西段最晚地震破裂发生在距今119±2 a之前, 中段发生在公元1890年前后, 南东段则发生在公元1948年, 显示出与段落之间应力触发作用有关的地震破裂事件沿断裂带单向迁移的特点. 相似文献
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甘孜－玉树断裂带的晚第四纪活动特征 总被引：17，自引：1，他引：17
在航、卫片解译的基础上，结合已有的区域地质填图成果，经过详细的野外观测研究，明确了甘孜－玉树断裂带最新地表活动形迹的空间展布特征。通过对断错地貌及新地层变形与位错的研究，结合（１４）Ｃ和热释光（ＴＬ）测龄结果，对断裂带晚第四纪以来的平均滑动速率进行了初步研究。结果表明，甘孜－玉树断裂带的平均滑动速率为：甘孜段水平滑动速率为３．４±０．３ｍｍ／ａ，垂直滑动速率为２．２±０．１ｍｍ／ａ；马尼干戈段水平滑动速率为７±０．７ｍｍ／ａ；邓柯段为７．２±１．２ｍｍ／ａ；当江段为７．３±０．６ｍｍ／ａ。 相似文献
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通过分析高精度数字化SPOT卫星影像 ,结合野外考察和年代学测试 ,对阿尔金南缘走滑断裂带的 3个典型走滑断层断错地貌点进行了研究。在安南坝沟 ,阿尔金南缘走滑断裂带一主要分支自 (9.36± 0 .73)kaBP以来的左旋滑动速率为 (7.5± 1.7)mm/a ;在七个泉子阿尔金南缘走滑断裂带有 4条分支 ,其中 1条规模较小的断层分支自 (13 86± 1 0 7)kaBP以来的左旋滑动速率为 (2 .3±0 5 )mm/a ,由此推断七个泉子附近断裂带全新世以来的滑动速率为 (6 .9± 1.5 )～ (9.2± 2 .0 )mm/a ;约马克其断裂带自 (4 .73± 0 .38)kaBP以来的左旋滑动速率为 (10 .6± 3.0 )mm/a。综合以上各点结果 ,阿尔金南缘走滑断裂带中段 88°30′E与 93°0 5′E之间全新世以来的水平滑动速率为 7～ 11mm/a ,与最新的GPS观测结果非常接近 相似文献
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遥感影像解译和野外地质地貌调查表明,龙陵-瑞丽断裂(南支)北段是以左旋走滑为主兼张性正断的区域性活动断裂。根据一些断错地貌点的大比例尺填图、实地测量及其年代学分析,确定了该断裂为全新世活动断裂,断裂晚更新世以来的平均水平滑动速率为2.2mm/a,平均垂直滑动速率为0.6mm/a;全新世以来的平均水平滑动速率为1.8～3.0mm/a,平均垂直滑动速率为0.5mm/a。断裂晚更新世以来的滑动速率在不同的时间尺度上变化不大,反映了该断裂晚更新世以来的活动强度比较平稳 相似文献
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A series of NWW striking faults are obliquely intersected by the NEE striking Altyn Tagh fault zone in the western Qilian Mountains. These faults were mostly active in late Quaternary and play an important role in accommodating regional lateral extrusion by both reverse and sinistral slip. Detailed studies on late Quaternary activity, tectonic transformation, paleoseismology, and strain partitioning not only significantly affect our recognition on seismogenic mechanism and zones of potential large earthquakes, but also provide useful information for exploring tectonic deformation mechanism in the northern Tibetan plateau. The Danghenanshan Fault, Yemahe-Daxueshan fault, and Altyn Tagh Fault form a triplet junction point at southwest of Subei county. The Yemahe-Daxueshan fault is one important branch fault in the western Qilian Mountains that accommodated eastward decreasing slip of the Altyn Tagh Fault, which was active in late Holocene, with a length up to 170km. Based on geometry and late Quaternary activity, the Yemahe-Daxueshan fault was subdivided into 3 segments, i.e. the Subei fault, Yemahe fault and Daxueshan Fault. The Yemahe Fault has the most prominent appearance among them, and is dominated by left-lateral slip with a little normal component. The heights of fresh scarps on this fault are only several tens of centimeters. We dug 2 trenches at the Zhazhihu site, and cleaned and reinterpreted one trench of previous studies. Then we interpreted trench profiles and paleoseismic events, and collected 14C and Optical Stimulated Luminescence samples to constrain event ages. Finally, we determined 3 events on the Yemahe fault with ages(6 830±30) a BP-(6 280±40) a BP, (5 220±30) a BP, (2 010±30) a BP, respectively. The elapsed time of most recent earthquake is(2 010±30) years before present, which is very close to the recurrence interval, so the possibility of major earthquakes on the Yemahe fault is relatively large. 相似文献
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The Bolokenu-Aqikekuduk fault zone(B-A Fault)is a 1 000km long right-lateral strike-slip active fault in the Tianshan Mountains. Its late Quaternary activity characteristics are helpful to understand the role of active strike-slip faults in regional compressional strain distribution and orogenic processes in the continental compression environment, as well as seismic hazard assessment. In this paper, research on the paleoearthquakes is carried out by remote sensing image interpretation, field investigation, trench excavation and Quaternary dating in the Jinghe section of B-A Fault. In this paper, two trenches were excavated on in the pluvial fans of Fan2b in the bulge and Fan3a in the fault scarp. The markers such as different strata, cracks and colluvial wedges in the trenches are identified and the age of sedimentation is determined by means of OSL dating for different strata. Four most recent paleoearthquakes on the B-A Fault are revealed in trench TC1 and three most recent paleoearthquakes are revealed in trench TC2. Only the latest event was constrained by the OSL age among the three events revealed in the trench TC2. Therefore, when establishing the recurrence of the paleoearthquakes, we mainly rely on the paleoearthquake events in trench TC1, which are labeled E1-E4 from oldest to youngest, and their dates are constrained to the following time ranges: E1(19.4±2.5)~(19.0±2.5)ka BP, E2(18.6±1.4)~(17.3±1.4)ka BP, E3(12.2±1.2)~(6.6±0.8)ka BP, and E4 6.9~6.2ka BP, respectively. The earthquake recurrence intervals are(1.2±0.5)ka, (8.7±3.0)ka and(2.8±3)ka, respectively. According to the sedimentation rate of the stratum, it can be judged that there is a sedimentary discontinuity between the paleoearthquakes E2 and E3, and the paleoearthquake events between E2 and E3 may not be recorded by the stratum. Ignoring the sedimentary discontinuous strata and the earthquakes occurring during the sedimentary discontinuity, the earthquake recurrence interval of the Jinghe section of B-A Fault is ~1~3ka. This is consistent with the earthquake recurrence interval(~2ka)calculated from the slip rate and the minimum displacement. The elapsed time of the latest paleoearthquake recorded in the trench is ~6.9~6.2ka BP. The magnitude of the latest event defined by the single event displacement on the fault is ~MW7.4, and a longer earthquake elapsed time indicates the higher seismic risk of the B-A Fault. 相似文献
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The Riyue Mt. Fault is a secondary fault controlled by the major regional boundary faults (East Kunlun Fault and Qilian-Haiyuan Fault). It lies in the interior of Qaidam-Qilianshan block and between the major regional boundary faults. The Riyue Mt. fault zone locates in the special tectonic setting which can provide some evidences for recent activity of outward extension of NE Tibetan plateau, so it is of significance to determine the activity of Riyue Mt. Fault since late Pleistocene to Holocene. In this paper, we have obtained some findings along the Dezhou segment of Riyue Mt. Fault by interpreting the piedmont alluvial fans, measuring fault scarps, and excavating trenches across the fault scarp. The findings are as follows:(1) Since the late Pleistocene, there are an alluvial fan fp and three river terraces T1-T3 formed on the Dezhou segment. The abandonment age of fp is approximately (21.2±0.6) ka, and that of the river terrace T2 is (12.4±0.11) ka. (2) Since the late Pleistocene, the dextral strike-slip rate of the Riyue Mt. Fault is (2.41±0.25) mm/a. In the Holocene, the dextral strike-slip rate of the fault is (2.18±0.40) mm/a, and its vertical displacement rate is (0.24±0.16) mm/a. This result indicates that the dextral strike-slip rate of the Riyue Mt. Fault has not changed since the late Pleistocene. It is believed that, as one of the dextral strikeslip faults, sandwiched between the the regional big left-lateral strike-slip faults, the Riyue Mt. Fault didn't cut the boundary zone of the large block. What's more, the dextral strike-slip faults play an important role in the coordination of deformation between the sub-blocks during the long term growth and expansion of the northeast Tibetan plateau. 相似文献
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Daliangshan fault zone (DFZ) constitutes an indispensable part of Xianshuihe-Xiaojiang fault system which is one of the main large continental strong earthquake faults in China.Puxiong Fault,the east branch of middle segment of DFZ,is the longest secondary fault.Its paleoseismic activity plays an important role in evaluating regional seismic activity level and building countermeasures of preventing and reducing the earthquake damage.The active fault mapping as well as the study of paleoseismological trench in recent years illustrates that Puxiong Fault is a slightly west-dipping high-angle left-lateral strike-slip fault with strong activity since late Pleistocene.Two trenches excavated across this fault reveal 2 and 3 paleoearthquakes that ruptured the fault at 8206 BC-1172 AD,1084-1549 AD,and 17434-7557 BC,1577-959 BC and 927-1360 AD,respectively.The OxCal model combining the results from both trenches and the another one in previous study across the fault with the historical earthquake record yields the elapsed time of~0.7ka of the latest paleoearthquake event,and the interval time is~2.3ka between the last two events.In the model,the penultimate event is considered to be recorded in all trenches.As all the three trenches are located at north part of the Puxiong Fault whose strike is apparently different from the south part,the~57km long north secondary segment is supposed to be the seismogenic structure of the paleoearthquake.According to the empirical scaling laws between magnitude and rupture length,the magnitude of the surface ruptured paleoearthquake is estimated to be more than M7 with the coseismic displacement~3.5m.However,the difference between the time of the paleoearthquake events on the middle and south segments of DFZ illustrates their independence as earthquake fracture units,and furthermore,the lower connectivity and the new generation of DFZ. 相似文献
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The relationship between the latest activity of active fault and seismic events is of the utmost importance. The Tan-lu fault zone in eastern China is a major fault zone, of which the active characteristics of the segments in Jiangsu, Shandong and Anhui has been the focus of research. This study takes the Dahongshan segment of the Tanlu Fault in Sihong County as the main research area. We carried out a detailed geological survey and excavated two trenches across the steep slope on the southwest side of the Dahongshan. Each trench shows fault clearly. Combining the comparative analysis of previous work, we identified and cataloged the late Quaternary deformation events and prehistoric earthquake relics, and analyzed the activity stages and behavior of this segment.
Fault gonge observed in the trench profiles shows that multiple earthquake events occurred in the fault. The faulting dislocated the Neogene sandstone, black gravel layer and gray clay layer. Brown clay layer is not broken. According to the relations of dislocated stratums, corresponding 14C and OSL samples were collected and dated. The result indicates that the Dahongshan segment of the Tanlu Fault has experienced strong earthquakes since the late Quaternary. Thrust fault, normal fault and strike-slip fault are found in the trenches. The microscopic analysis of slices from fault shows that there are many stick-creep events taking place in the area during the late Quaternary. Comprehensive analysis shows that there have been many paleoearthquakes in this region since the late Quaternary, the recent active time is the late Pleistocene, and the most recent earthquake event occurred in(12~2.5ka BP).
The neotectonic activity is relatively weak in the Anhui segment(south of the Huaihe River)of Tanlu fault zone. There are difficulties in the study of late Quaternary activity. For example, uneven distribution of the Quaternary, complex geological structure, larger man-made transformation of surface and so on. The progressive research may be able to promote the study on the activity of the Anhui segment of Tanlu fault zone. 相似文献
18.
WANG Ming-ming HE Yu-lin LIU Shao WANG Shi-yuan MA Chao ZHANG Wei JIA Zhao-liang 《地震地质》2018,40(4):738-752
The Ganzi-Yushu Fault, the boundary of Bayan Har active tectonic block, Qiantang active tectonic block and Sichuan-Yunan active tectonic block, is a sinistral strike-slip fault zone with intensive Holocene activity. Thus, the study of activity characteristics and rupture behavior of paleoearthquakes in the late Quaternary on the Ganzi-Yushu Fault is of fundamental importance for understanding the future seismic risk of this fault. The southeast section of Ganzi-Yushu Fault is made up of three segments of Ganzi, Manigange and Dengke, where a MS7.3 earthquake in 1866, a MS7.7 earthquake in 1854 and a MS7.3 in 1896 occurred, respectively. There is still lack of in-depth study on the active features and the cascading rupture possibility of these segments, which hindered the evaluation of seismic risk for the southeast section of Ganzi-Yushu Fault. By the means of field geological survey and micro topography measurement, this paper studied the geological and geomorphological features of the southeast section of the Ganzi-Yushu Fault. The results show that the Ganzi and Dengke segments show obvious extension movement, in addition to the left-lateral movement. For Manigange segment, the characteristics of the movement are mainly left-lateral strike-slip and thrusting, and the maximum vertical displacement of the Holocene strata is greater than 2m. In part areas, the movement is normal faulting, which perhaps relates to the left stepping zone in the local stress environment. Therefore, combining the research results such as the fracture distribution in different motion characteristics, rupture behavior of paleoearthquakes, and the distribution of historical earthquake surface ruptures, we divide the southeast section of Ganzi Yushu Fault into Ganzi, Manigange and Dengke segment, and consider the Yakou and the Dengke Basin as the stepovers and the segments' boundaries. As the small scale of impermanent barriers including Dengke Basin and the ridge near Yakou, of which the width is about 1~2km, they may be broken through in great earthquake rupture in future. A trench was excavated in Zhuqing township to investigate the paleoearthquakes on the Manigange segment, radiocarbon dating was employed and 3 paleoseismic events were revealed in the Zhuqing trench, which are the seismic events occurring respectively at 3875~3455BC, after 775BC, and the latest one that ruptured the surface. Compared with the previous results of paleoseismology in the southeast section of Ganzi-Yushu Fault, it is found that the paleoseismic events in the Manigange segment are obviously different with that in Ganzi segment and Dengke segment. Due to the lack of sufficient data on the southeast section of the Ganzi-Yushu Fault, it still needs further discussion whether the cascade-rupturing between these segments exists. 相似文献
19.
The Xiaojiang fault zone is located in the southeastern margin of the Tibetan plateau, the boundary faults of Sichuan-Yunnan block and South China block. The largest historical earthquake in Yunnan Province, with magnitude 8 occurred on the western branch of the Xiaojiang Fault in Songming County, 1833. Research on the Late Quaternary surface deformation and strong earthquake rupture behavior on the Xiaojiang Fault is crucial to understand the future seismic risk of the fault zone and the Sichuan-Yunnan region, even crucial for the study of tectonic evolution of the southeastern margin of Tibetan plateau. We have some new understanding through several large trenches excavated on the western branch of the Xiaojiang fault zone. We excavated a large trench at Caohaizi and identified six paleoseismic events, named U through Z from the oldest to the youngest. Ages of these six events are constrained at 40000-36300BC, 35400-24800BC, 9500BC-500AD, 390-720AD, 1120-1620AD and 1750AD-present. The Ganhaizi trench revealed three paleoearthquakes, named GHZ-E1 to GHZ-E3 from the oldest to the youngest. Ages of the three events are constrained at 3300BC-400AD, 770-1120AD, 1460AD-present. The Dafendi trench revealed three paleoearthquakes, named E1 to E3 from the oldest to the youngest, and their ages are constrained at 22300-19600BC, 18820-18400BC, and 18250-present. Caohaizi and Ganhaizi trenches are excavated on the western branch of the Xiaojiang Fault, the distance between them is 400m. We constrained four late Holocene paleoearthquakes with progressive constraining method, which are respectively at 500-720AD, 770-1120AD, AD 1460-1620 and 1833AD, with an average recurrence interval of 370~440a. Large earthquake recurrence in the late Holocene is less than the recurrence interval of~900a as proposed in the previous studies. Thus, the seismic hazard on the Xiaojiang Fault should be reevaluated. We excavated a large trench at Dafendi, about 30km away south of Caohaizi trench. Combining with previous paleoseismological research, it is found that the western branch of Xiaojiang Fault was likely to be dominated by segmented rupturing in the period from late of Late Pleistocene to early and middle Holocene, while it was characterized by large earthquakes clustering and whole segment rupturing since late Holocene. 相似文献
20.
柯坪推覆构造的根部断裂记录到的地震活动相对较弱,以至于多数学者认为该断裂晚第四纪以来活动性不强。笔者根据遥感影像解译和野外调查得到迈丹断裂的几何展布,确认F3阿合奇段为最新地表破裂带,并通过一系列河流阶地的左旋位移测量确定其晚更新世以来有过走滑活动。结合地貌测量和探槽开挖得到断层垂直错距,探槽揭示的古地震事件发生在距今(1.76±0.22)ka之后,根据现场考察获得的活动构造定量数据,依据不同震级与地表破裂关系式推算出该次古地震震级为7.5级。研究成果可能对区域活动断裂的研究以及区域活动构造图像的完整性提供基础资料,同时最新地表破裂证据的发现可能有助于更新认识该断裂的危险性。 相似文献