SUMMARY

The study of the dynamic triggering of earthquakes and tremors during large earthquakes at faraway distances is an active area of research. This type of remote dynamic triggering is often found in subduction zones. The Iranian plateau is part of the Alpine–Himalayan orogenic system and hosts different collision styles of deformation and significant strike-slip faults. Using 13 yr (26 December 2004–8 September 2017) of continuous data of Iranian National Seismic Network (INSN) and some dense temporary networks, for the first time we carried a systematic study of dynamic triggering in Iran during 47 recent large earthquakes with magnitude and depth ranges of 6.4–9.1 and 8–90 km, respectively. We explored the local catalogue of 124 805 events with a magnitude of completeness (M_c) of 1.8 for the study of dynamic triggering but did not find any convincing evidence of dynamic triggering from the catalogue. The waveform data of 24 hr duration around the main events were analysed to find possible dynamic triggering through manual analysis of the waveform, STA/LTA, and beta statistics and found the triggering. We found dynamic triggering in Iran during Sumatra, 26 December 2004, M_w 9.1; Tohoku-Oki, 11 March 2011, M_w 9.1; Indian Ocean, 11 April 2012, M_w8.6 and Baluchistan, 24 September 2013 earthquakes and also possible triggering during Sumatra, 12 September 2007, M_w8.5. Only ∼10 per cent of the analysed earthquakes produced dynamic triggering. The triggering initiates during the passage of high amplitude Love waves and continues through the passage of the Rayleigh waves. We found north, central and eastern regions are more probable for triggering than Zagros and Makran regions. The instances of triggering were not restricted to only a small region, but instead, occurred at multiple locations. We find the onset of tremor correlates with very small stress changes, on the order of 1 kPA. However, the amplitude of the dynamic stresses is not a sufficient condition since some of the areas with considerably larger dynamic stresses are not triggered any seismicity in the region. The backazimuth angle of ∼50° and ∼120° seems to play an important role in the triggering. Teleseismic waves most probable for triggering local earthquakes within NW and central Iran include incoming surface waves with an incident angle of ∼60°–90° with respect to the local fault fabric.

中文翻译：

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伊朗的远程触发：峰值动态应力不是触发的主要驱动力

概括

对远距离大地震中地震和地震的动态触发的研究是一个活跃的研究领域。这种类型的远程动态触发通常在俯冲带中被发现。伊朗高原是高山－喜马拉雅造山系统的一部分，拥有不同的变形碰撞方式和明显的走滑断层。我们使用伊朗国家地震台网（INSN）和一些密集的临时网络的13年（2004年12月26日至2017年9月8日）的连续数据，首次对近期发生的47次大地震在伊朗的动态触发进行了系统的研究。和深度范围分别为6.4–9.1和8–90 km。我们探索了124 805个事件的本地目录，它们的完整性（M _c），以研究动态触发，但没有从目录中找到任何令人信服的动态触发证据。对主要事件周围24小时持续时间的波形数据进行了分析，以通过手动分析波形，STA / LTA和beta统计信息来找到可能的动态触发，并找到触发。我们在2004年12月26日苏门答腊（M _w 9.1）期间发现了伊朗的动态触发；东北冲，2011年3月11日，M _w 9.1; 印度洋，2012年4月11日，M _w 8.6和Bal路支斯坦，2013年9月24日地震，也可能是苏门答腊2007年9月12日，M _w8.5。分析的地震中只有约10％产生了动态触发。触发在高振幅Love波通过时开始，并在Rayleigh波通过时继续。我们发现北部，中部和东部地区比Zagros和Makran地区更容易触发。触发的实例不仅限于一个很小的区域，而是发生在多个位置。我们发现震颤的发生与很小的压力变化相关，约为1 kPA。但是，动应力的幅度不是一个充分的条件，因为某些动应力相当大的区域在该区域不会触发任何地震活动。〜50°和〜120°的后方位角似乎在触发中起重要作用。