Abstract

Under certain suitable geological conditions, anthropogenic seismicity due to gold/coal mining, geothermal and natural gas/oil production, filling of artificial water reservoirs, and high-pressure fluid injection has been reported globally. The reservoir-triggered seismicity (RTS) is most prominent, having been reported from hundreds of with at least five sites where earthquakes exceeding M 6 occurred, claiming human lives and destruction of properties. The most important correlate for RTS to occur is the height of water column in the reservoir. Certain common characteristics of the RTS sequences have been identified, which discriminate them from normal earthquake sequences. Factors influencing RTS include the highest water levels reached in the reservoir, duration of the retention of high-water levels and rate of loading/unloading. The mechanism of RTS is reviewed. The absence of knowledge of physical properties of rocks and fluids in the fault zone does not permit us to comprehend the RTS mechanism. Koyna, India, is found to be a very suitable site for such investigations as the earthquakes have been occurring in a small region of 20 × 30 km, at shallow depths (mostly within 8 km), with no other seismic source in the vicinity, and the region being accessible for all kinds of observation and investigations. The suitability of Koyna for setting up of a deep borehole laboratory was discussed during International Continental Drilling Program (ICDP) workshop in 2011 and accepted. Suggestions were made for some additional scientific works, which were completed during 2011–2014. The second ICDP workshop in 2014 approved of going ahead. A 3-km-deep Pilot Borehole has been completed in the vicinity of Donachiwada fault that hosted the main 10 December 1967 M 6.3 earthquake and several earthquakes of M ~ 5. The investigations being carried out are providing the necessary input to set up the proposed ~ 7-km-deep borehole laboratory. In this article, an overview of RTS globally and at Koyna, India, specifically is focused.

Article Highlights

• Global review of the reservoir-triggered seismicity (RTS) sites

• Factors influencing RTS, their common characteristics and mechanism

• Continued seismicity at Koyna, India, and near-field studies

中文翻译：

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人工水库触发的地震活动（RTS）：最突出的人为地震活动

摘要

在某些合适的地质条件下，全球报道了由金/煤开采、地热和天然气/石油开采、人工水储层充填和高压流体注入引起的人为地震活动。水库触发的地震活动 (RTS) 最为突出，据报道，数百个地点至少有五个发生超过 M 6 的地震，造成人员生命和财产破坏。RTS 发生的最重要的相关因素是水库中水柱的高度。已经确定了 RTS 序列的某些共同特征，这些特征将它们与正常的地震序列区分开来。影响 RTS 的因素包括水库中达到的最高水位、高水位保持的持续时间和装载/卸载速度。回顾了RTS的机制。由于缺乏对断裂带岩石和流体物理特性的了解，我们无法理解 RTS 机制。印度科伊纳被认为是一个非常适合进行此类调查的地点，因为地震发生在 20 × 30 公里的小区域，深度较浅（大部分在 8 公里以内），附近没有其他震源，并且该区域可以进行各种观察和调查。在 2011 年的国际大陆钻探计划 (ICDP) 研讨会上讨论了 Koyna 是否适合建立深孔实验室并被接受。对一些额外的科学工作提出了建议，这些工作在 2011-2014 年间完成。2014 年第二届 ICDP 研讨会批准继续进行。在 1967 年 12 月 10 日发生 M 6.3 级地震和数次 M ~ 5 级地震的 Donachiwada 断层附近完成了一个 3 公里深的先导钻孔。正在进行的调查为建立拟议的~ 7 公里深的钻孔实验室。在本文中，特别关注全球和印度 Koyna 的 RTS 概述。

文章重点

• 水库触发地震活动 (RTS) 站点的全球回顾

• 影响 RTS 的因素、它们的共同特点和作用机制

• 印度科伊纳的持续地震活动和近场研究