Paleoearthquakes and slip rates of the North Tabriz Fault, NW Iran: preliminary results
Paleoearthquakes and slip rates of the North Tabriz Fault, NW Iran: preliminary results
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DOI：
10.4401/ag-3461
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发表时间：
2003-12
影响因子：
1
通讯作者：
K. Hessami;D. Pantosti;Hadi Tabassi-;E. Shabanian;M. Abbassi;K. Feghhi;S. Solaymani
中科院分区：
文献类型：
--
作者：
K. Hessami;D. Pantosti;Hadi Tabassi-;E. Shabanian;M. Abbassi;K. Feghhi;S. Solaymani
北大不里士断层是伊朗西北部的一个主要地震断层。该断层上最近一次破坏性地震发生在 1721 年，导致东南断层段破裂，并于 1780 年导致西北断层段破裂。了解该断层的地震行为对于评估伊朗主要城市之一大不里士的危险至关重要；这座城市在 1721 年和 1780 年的事件中都遭受了严重破坏。我们的研究区位于大不里士市以西的西北断层段。我们进行了地貌和挖沟调查，这使我们能够识别自晚更新世以来重复断层事件的证据。从战壕中，我们发现了过去 3.6ka 期间至少四次事件的证据，最近的一次是 1780 年的地震。根据不同的方法，发现每次事件的水平滑移和滑移率分别在 4 ± 0.5 m 和 3.1-6.4 mm/年的范围内。我们还尝试估计平均复发间隔，似乎在 350-1430 年范围内，平均复发间隔为 821 ± 176 年。根据这些结果，北大不里士断层的西北段似乎在不久的将来不会出现重大地震潜力，但是，对断层东南段的了解还不够，无法得出类似的结论。
The North Tabriz Fault is a major seismogenic fault in NW Iran. The last damaging earthquakes on this fault occurred in 1721, rupturing the southeastern fault segment, and in 1780, rupturing the northwestern one. The understanding of the seismic behavior of this fault is critical for assessing the hazard in Tabriz, one of the major cities of Iran; the city suffered major damage in both the 1721 and 1780 events. Our study area is located on the northwestern fault segment, west of the city of Tabriz. We performed geomorphic and trenching investigations, which allowed us to recognize evidence for repeated faulting events since the Late Pleistocene. From the trenches, we found evidence for at least four events during the past 3.6 ka, the most recent one being the 1780 earthquake. On the basis of different approaches, horizontal slip per event and slip rates are found in the ranges of 4 ± 0.5 m and 3.1-6.4 mm/yr, respectively. We also attempted an estimate of the average recurrence intervals which appears to be in the range 350-1430 years, with a mean recurrence interval of 821 ± 176 years. On the basis of these results, the northwestern segment of the North Tabriz Fault does not appear to present a major seismic potential for the near future, however, not enough is known about the southeastern segment of the fault to make a comparable conclusion.