THE HOLOCENE SEISMIC EVIDENCE ON SOUTHERN SEGMENT OF THE RED RIVER FAULT ZONE |
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| Authors: | LI Xi RAN Yong-kang CHEN Li-chun WANG Hu YU Jiang ZHANG Yan-qi XIE Ying-qing |
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| Affiliation: | 1.Earthquake Administration of Yunnan Province, Kunming 650224, China;2.Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China |
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| Abstract: | Nine earthquakes with M≥6 have stricken the northern segment of the Red River fault zone since the historical records, including the 1652 Midu M7 earthquake and the 1925 Dali M7 earthquake. However, there have been no earthquake records of M≥6 on the middle and southern segments of the Red River Fault, since 886 AD. Is the Red River fault zone, as a boundary fault, a fault zone where there will be not big earthquake in the future or a seismogenic structure for large earthquake with long recurrence intervals?This problem puzzles the geologists for a long time. Through indoor careful interpretation of high resolution remote sensing images, and in combination with detailed field geological and geomorphic survey, we found a series of fault troughs along the section of Gasha-Yaojie on the southern segment of the Red River fault zone, the length of the Gasha-Yaojie section is over ten kilometers. At the same time, paleoseismic information and radiocarbon dating result analysis on the multiple trenches show that there exists geological evidence of seismic activity during the Holocene in the southern segment of the Red River fault zone. |
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| Keywords: | the Red River fault zone seismogenic structure of large earthquake multiple trenches paleoearthquake the Holocene active fault |
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