Hydrologic responses to earthquakes and a general metric

Abstract

Hydrologic responses to earthquakes, including liquefaction, changes in stream and spring discharge, changes in the properties of groundwater such as geochemistry, temperature and turbidity, changes in the water level in wells, and the eruption of mud volcanoes, have been documented for thousands of years. Except for some water-level changes in the near field which can be explained by poroelastic responses to static stress changes, most hydrologic responses, both within and beyond the near field, can only be explained by the dynamic responses associated with seismic waves. For these responses, the seismic energy density e may be used as a general metric to relate and compare the various hydrologic responses. We show that liquefaction, eruption of mud volcanoes and increases in streamflow are bounded by e $ 10 )1 J m )3 ; temperature changes in hot springs are bounded by e $ 10 )2 J m )3 ; most sustained groundwater changes are bounded by e $ 10 )3 J m )3 ; geysers and triggered seismicity may respond to seismic energy density as small as 10 )3 and 10 )4 J m )3 , respectively. Comparing the threshold energy densities with published laboratory measurements, we show that undrained consolidation induced by dynamic stresses can explain liquefaction only in the near field, but not beyond the near field. We propose that in the intermediate field and far field, most responses are triggered by changes in permeability that in turn are a response to the cyclic deformation and oscillatory fluid flow. Published laboratory measurements confirm that changes in flow and time-varying stresses can change permeability, inducing both increases and decreases. Field measurements in wells also indicate that permeability can be changed by earthquakes in the intermediate field and far field. Further work, in particular field monitoring and measurements, are needed to assess the generality of permeability changes in explaining far-field hydrologic responses to earthquakes.

Mechanism of co-seismic water level change following four great earthquakes – insights from co-seismic responses throughout the Chinese mainland

“…Purple squares show data from a global catalog of well responses (Wang and Manga, 2010). Stars show selected co-seismic data recorded in Devils hole (Weingarten and Ge, 2014), and purple circles show co-seismic M 2 earth tide phase shift changes in different wells.…”

“…(2) groundwater wells in Taiwan responding to the 1999 ChiChi Mw 7.3 earthquake and 2006 Hengchun Mw 7.0 earthquake ; (3): data from New Zealand, responses to the 2010 Mw 7.1 Darfield (Canterbury) earthquake (Cox et al, 2012); (4) data from an earlier global catalog of well responses (Wang and Manga, 2010) and responses recorded in Devils Hole, Nevada (Weingarten and Ge, 2014).…”

“…This parameter is approximately proportional to the square of the peak ground velocity (Wang et al, 2006), which in turn is proportional to the dynamic strain . This relationship was used to interpret a global data set of different types of hydrological response in order to identify the different thresholds for the various hydrological responses (Wang and Manga, 2010).…”

Water-table and discharge changes associated with the 2016–2017 seismic sequence in central Italy: hydrogeological data and a conceptual model for fractured carbonate aquifers

“…Recorded hydrological changes for the 2016-2017 earthquakes may be preliminarily attributed to the pore pressure propagation in the aquifers, which would be followed by a sustained discharge increase attributable to fracture cleaning, mobilizing fine particles from fractures Wang and Manga 2010;Adinolfi Falcone et al 2012), as reflected by turbidity increase, clearly recorded in several monitoring points (e.g. R1, S5, S11, S12).…”

“…7 Distribution of earthquake-triggered hydrogeological changes as a function of earthquake magnitude (horizontal axis) and epicentral distance (vertical axis). Also plotted are the contours (oblique lines) of constant seismic energy density (Wang and Manga 2010) and the domains where different types of coseismic water level responses occur (Wang and Chia 2008). The triangles represent the water level changes in wells or in rivers, the dots the discharge changes in spring or rivers.…”