闻学泽. 2018: 巴颜喀拉块体东边界千年破裂历史与2008年汶川、2013年芦山和2017年九寨沟地震. 地震学报, 40(3): 255-267. DOI: 10.11939/jass.20170211
引用本文: 闻学泽. 2018: 巴颜喀拉块体东边界千年破裂历史与2008年汶川、2013年芦山和2017年九寨沟地震. 地震学报, 40(3): 255-267. DOI: 10.11939/jass.20170211
Wen Xueze. 2018: The 2008 Wenchuan, 2013 Lushan and 2017 Jiuzhaigou earthquakes, Sichuan, in the last more than one thousand years of rupture history of the eastern margin of the Bayan Har block. Acta Seismologica Sinica, 40(3): 255-267. DOI: 10.11939/jass.20170211
Citation: Wen Xueze. 2018: The 2008 Wenchuan, 2013 Lushan and 2017 Jiuzhaigou earthquakes, Sichuan, in the last more than one thousand years of rupture history of the eastern margin of the Bayan Har block. Acta Seismologica Sinica, 40(3): 255-267. DOI: 10.11939/jass.20170211

巴颜喀拉块体东边界千年破裂历史与2008年汶川、2013年芦山和2017年九寨沟地震

The 2008 Wenchuan, 2013 Lushan and 2017 Jiuzhaigou earthquakes, Sichuan, in the last more than one thousand years of rupture history of the eastern margin of the Bayan Har block

  • 摘要: 以巴颜喀拉块体东边界活动构造带为研究区,本文首先分析了该区最近一千多年的地震历史及强震活动随时间的变化,确定了2008年汶川MS8.0地震、2013年芦山MS7.0地震和2017年九寨沟MS7.0地震这3次事件在这一强震活动历史中的位置,进而在圈绘长期强震破裂区图像的基础上鉴别主要活动断裂带上的地震空区。结果主要表明:研究区在最近约一千年中经历了一个强震轮回的3个阶段,包括一个平静期的后半部(1630年之前)、1630—1878年之间的过渡期以及1879年以来的强震期。后两个阶段可能代表了该构造带在经过更早、可能二三千年长的平静期或应变积累期之后出现的长达数百年、从“预释放”期(1630—1878年)到“主释放”期(1879年以来)的强震发生过程;在主释放期应变能释放呈明显加速,四川2008年汶川、2013年芦山以及2017年九寨沟地震是发生在主释放期中的3次最新事件,但是由这3次事件的发生还难以判断主释放期是否已经结束;已圈绘出研究区及其邻近地区若干活动断裂段上存在长期缺少大地震破裂的地震空区,未来仍应注意在这些地震空区再次发生大地震的危险性。

     

    Abstract: By taking the active tectonic belt along the eastern margin of the Bayan Har block as the study region, this paper first examines the earthquake history over the last 1 000 years and the temporal variation in strong earthquake activity, and determines the temporal positions in this history of the most-recent three major events, the 2008 MS8.0 Wenchuan, 2013 MS7.0 Lushan and 2017 MS7.0 Jiuzhaigou earthquakes. Then, based on mapping historically ruptured areas the author identifies the seismic gaps along main active fault zones in and near the study region. The result mainly shows that the study region has experienced three stages of a strong-earthquake cycle during the last about 1 000 years, including the last half of the quiet period before 1630, the transitional period from 1630 to 1878, and the strong-event occurrence period since 1879. The last two periods together have a total duration of several hundred of years, and probably represent such a seismicity process in which the study active tectonic belt went through from the pre-release episode (between 1630 and 1878) to the main release episode (since 1879), following an earlier quiescence period of probably 2 000 to 3 000 years in length for strain accumulation. Accelerating strain energy release appears obviously in the main release episode. The three events of the 2008 MS8.0 in Wenchuan, 2013 MS7.0 in Lushan and 2017 MS7.0 in Jiuzhaigou, Sichuan, are the most-recent ones occurred in the main release episode. However, it still remains unknown whether the main release episode has closed or not yet after the occurrences of the latest three events. Several seismic gaps are identified and mapped along some segments of the major active fault zones in and near the study region, which have had no ruptures of major earthquakes for long time. So, enough attention should be paid to the seismic potentials for major earthquakes occurring on these seismic gaps in the not far future.

     

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