Review: Research Results in Hydroseismicity from 1987 to 2009

Abstract

Most natural crustal earthquakes fall into one of two categories:(1) those associated with the dynamics of plate tectonics, or (2) those associated with the elements of the hydrologic cycle. This paper presents a comprehensive listing of published examples of hydroseismicity, a hypothesis that attributes most intraplate and near-intraplate earthquakes to the dynamics of the hydrologic cycle, which includes hurricanes and typhoons. Results from 30 worldwide studies of earthquake-rainfall correlations published during the past 22 years are referenced. These investigations were conducted in both intraplate and plate marginal environments on five continents. Collectively, they provide strong support for the hydroseismicity hypothesis as a viable explanation via pore-fluid-pressure diffusion for the occurrence of many earthquakes, regardless of the host tectonic regime. Signatures of pore-fluid-pressure diffusion in the Earth's crust are ubiquitous. Slow earthquakes result from crack development driven by pore-fluid-pressure diffusion. These earthquakes, also called silent earthquakes, take days, weeks, or even months to release energy instead of seconds or minutes as in normal earthquakes. Typhoons can trigger slow earthquakes in some areas. Hurricanes are believed to have triggered earthquakes in the eastern United States. Their explanation is provided for the most part by Biot's theory for wave propagation and pore-fluid-pressure diffusion in poroelastic media.

Monsoon-induced earthquake activity in Talala, Gujarat, India

“…diffusivity D = 5 m 2 s −1 , which is in the order of previously estimated values for fracture systems (Costain & Bollinger 2010), almost all earthquakes in the study region occurred inside these periods indicating that reservoir-induced stress variations might be one triggering mechanism for the observed earthquakes. Thus we analyse in more detail both reservoir and rainfall triggering in the following sections.…”

“…The monsoon supplies the river Hiran with water, which is passing through the seismicity region Talala and is impounded at the two dams Hiran I and II (see Fig. 1 1990 recording flow rates which can be in general used as proxy for groundwater level changes (Costain & Bollinger 2010). We use these observed hydraulic parameters, which are presented in Fig.…”

“…Usually river flow (runoff) data can be alternatively used to estimate the groundwater changes (Costain & Bollinger 2010). However, the Hiran river is not perennial and only flows in monsoon periods, when the stream is stored in dam Hiran I and II.…”

“…Crustal seismicity has been partly explained by hydromechanical coupling where increased pore fluid pressure reduces the effective normal stress and thus the strength of faults, promoting earthquake failures (Costain & Bollinger 2010). Triggering of earthquakes is evident for fluid injections in wells, for example (Zoback & Harjes 1997;Shapiro et al 2003;Fischer et al 2008), where engineering data are available and dense monitoring systems are installed.…”

Advancing geodesy in the U.S. Midcontinent: workshop report

“…Given boundary forces, a model of expected crustal strain could then be developed, and, if warranted, stations placed to test and refine this model. Improved modeling of local sources of loading-including the role of deglaciation (Grollimund and Zoback, 2001), intracrustal heterogeneity (Kenner and Segall, 2000;Pollitz and others, 2001), erosion of surficial sediment (Calais and others, 2010), and shorter term hydrological loading (for example, Costain and Bollinger, 2010)-are critically needed to inform the design of geodetic networks. Additional CGPS sites in the region are also of interest to study these loading processes.…”