Surface Fault Breaks, Aftershock Distribution, and Rupture Process of the 17 August 1999 İzmit, Turkey, Earthquake
Surface Fault Breaks, Aftershock Distribution, and Rupture Process of the 17 August 1999 İzmit, Turkey, Earthquake
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1999年8月17日土耳其伊兹米特地震的地表断层断裂、余震分布和破裂过程
DOI：
10.1785/0120000815
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发表时间：
2002
影响因子：
3
通讯作者：
A. M. Işikara
中科院分区：
文献类型：
--
作者：
L. Gülen;A. Pınar;D. Kalafat;N. Ozel;G. Horasan;M. Yilmazer;A. M. Işikara
陆地表面断层断裂现场研究、余震研究以及1999年8月17日伊兹米特地震（M w 7.4）复杂远震体波分析的结果表明，北安纳托利亚断裂带北岸在东经29.1°至31.1°之间发生了破裂，最大总断层破裂长度约为200公里。 1999 年 11 月 12 日的迪兹杰地震（兆瓦级 7.2 级）使地表断层断裂向东又延伸了 41 公里。余震的排列描绘了陆地上的断层破裂，并将其延伸到赫塞克三角洲以西，深入马尔马拉海，直至东经 29.1°。我们已经确定了六个断层破裂段：其中两个位于赫塞克三角洲的西部，四个位于东部。
破裂过程分析表明，破裂在空间和时间上分为两个阶段，估计总标量地震矩为 2.42 × 1020 N·m。第一阶段始于伊兹米特附近的震中，并以不对称的方式传播——先向东，然后向西，总标量矩为 1.6 × 1020 N·m，主要表现为右旋走滑断层，随后发生一次次事件，使断裂进一步向东延伸。第二阶段发生在源区的西端和东端，破裂了马尔马拉海内赫塞克三角洲以西的两个部分以及阿基亚齐和戈利亚卡之间的两个部分。破裂过程分析表明，主震期间有六个断层破裂：其中四个在陆地上，两个在马尔马拉海内。 1.2 × 1020 N m 的主要力矩释放位于伊兹米特湾最东端和 Akyazi 之间 64 公里长的萨潘卡段，估计最大滑移为 5.3 m。高居克路段长 30 km，力矩释放约为 3.7 × 1019 N·m，估计该路段滑移量为 4.1 m。破裂过程分析表明，Akyazi 和 Golyaka 之间有两条 20 公里长的断裂带，断裂位置为 N70°E。这些段上的标量力矩释放为 2.7 × 1019 和 1.9 × 1019 N m，估计偏移量分别为 2.2 和 1.6 m。最后两次子事件发生在赫塞克三角洲以西的亚洛瓦段和马尔马拉海内，估计偏移量分别为 1.3 和 1.0 m。
手稿于 2000 年 8 月 20 日收到。
The results obtained from field studies of surface fault breaks on land, aftershock studies, and analysis of complex teleseismic body waves of the 17 August 1999 Izmit earthquake ( M w 7.4) indicate that the northern strand of the North Anatolian Fault Zone had been ruptured between 29.1° E and 31.1° E, with a maximum total fault rupture length of about 200 km. The 12 November 1999 Duzce earthquake ( M w 7.2) extended the surface fault break an additional 41 km to the east. Alignment of the aftershocks delineates the fault rupture on land and extends it to the west of the Hersek Delta, well into the Marmara Sea, to 29.1° E longitude. We have identified six fault rupture segments: two of them are located to the west of the Hersek Delta, and four are located to the east.
Rupture process analysis suggests two stages of rupture separated in space and time, with an estimated total scalar seismic moment of 2.42 × 1020 N m. The first stage initiated at the epicenter, near Izmit, and propagated asymmetrically—first eastward and then westward with a total scalar moment of 1.6 × 1020 N m, showing predominantly right-lateral strike-slip faulting followed by a minor subevent extending the rupture further east. The second stage took place at the western and eastern ends of the source area, rupturing two segments within the Marmara Sea, west of the Hersek Delta, and two segments between Akyazi and Golyaka. The rupture process analysis indicates that six fault segments were ruptured during the mainshock: four of them on land and two within the Marmara Sea. The major moment release of 1.2 × 1020 N m is found on the 64-km-long Sapanca segments located between the easternmost tip of the Gulf of Izmit and Akyazi, with an estimated maximum slip of 5.3 m. The moment release on the Golcuk segment, with a length of 30 km, is about 3.7 × 1019 N m, and the estimated slip on this segment is 4.1 m. Rupture process analysis suggests two 20-km-long segments between Akyazi and Golyaka striking N70°E. The scalar moment releases on these segments are 2.7 × 1019 and 1.9 × 1019 N m, with estimated offsets of 2.2 and 1.6 m, respectively. The last two subevents took place to the west of the Hersek Delta on the Yalova segment and within the Marmara Sea, with estimated offsets of 1.3 and 1.0 m, respectively.
Manuscript received 20 August 2000.