Crustal Deformation and Seismicity Modulated by Groundwater Recharge of Karst Aquifers

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Publication Date

11-14-2018

Publication Title

Geophysical Research Letters

Volume Number

45

Issue Number

22

Abstract

Triggered seismicity in karst regions has been explained assuming the existence of a hydraulically connected fracture system and downward diffusion of surface pore pressures. Karst systems are, in fact, able to swiftly channel large amount of rainfall through networks of conduits increasing the hydraulic head loading upon the fluid‐saturated, poroelastic crust. Here we use Global Positioning System and hydrological and seismicity data to show that poroelastic strain in the shallow crust (0–3.5 km) controls seasonal and multiannual modulation of seismicity along the Irpinia Fault Zone (Southern Italy) without requiring a hydraulically connected fracture system from the surface to hypocentral depths. We suggest that groundwater recharge of karst aquifers along the Irpinia Fault Zone produces stress perturbations large enough to modulate strain accumulation and seismicity and temporarily modify the probability of nucleation of seismic events such as the 1980 Irpinia, M S 6.9, earthquake.

Keywords

Karst, Seismicity, Earthquake faults, Groundwater recharge, Hydrology

Document Type

Article

Digital Object Identifier (DOI)

https://doi.org/10.1029/2018GL079794

Language

English

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