Seismicity, Fault Rupture and Earthquake Hazards in Slowly Deforming Regions
Palaeoseismic records and seismological data from continental interiors increasingly show that these areas of slow strain accumulation are more subject to seismic and associated natural hazards than previously thought. Moreover, some of our instincts developed for assessing hazards at plate boundaries might not apply here. Hence assessing hazards and drawing implications for the future is challenging, and how well it can be done heavily depends on the ability to assess the spatiotemporal distribution of past large earthquakes. This book explores some key issues in understanding hazards in slowly deforming areas. Examples include classic intraplate regions, such as Central and Northern Europe, Mongolia, Inner Mongolia, Australia, and North and South America, and regions of widely distributed strain, such as the Tien Shan Mountains in Central Asia. The papers in this volume are grouped into two sections. The first section deals with instrumental and historical earthquake data and associated hazard assessments. The second section covers methods from structural geology, palaeoseismology and tectonic geomorphology, and incorporates field evidence.
Groundwater recharge as the trigger of naturally occurring intraplate earthquakes
Published:January 01, 2017
John K. Costain, 2017. "Groundwater recharge as the trigger of naturally occurring intraplate earthquakes", Seismicity, Fault Rupture and Earthquake Hazards in Slowly Deforming Regions, A. Landgraf, S. Kübler, E. Hintersberger, S. Stein
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I explore the hypothesis that most intraplate earthquakes and their aftershock sequences are triggered by pore-fluid pressure increases. As proposed in this paper, data from the magnitude 5.7 Virginia earthquake of 23 August 2011 show that this is a two-step process. (1) First, from areas where there is greater than normal meteoric recharge, pore-fluid pressure diffusion by means of Biot slow waves transfers more pore-fluid pressure towards a future hypocentre. Here the cumulation of Biot slow waves produces a steady increase in pore-fluid overpressure until a main shock is triggered. (2) Then, aftershocks occur in the zone reaching from...