Climate- and Weather-Driven Solid-Earth Deformation and Seismicity

Abstract

There is long-standing interest in the interactions between atmospheric and hydrological processes and solid Earth deformation, including the occurrence of earthquakes. Here, we review evidence for the effects of climatic processes and weather on deformation and seismicity in the lithosphere over a wide range of time scales, ranging from load cycles associated with the ice ages to the effects of short-term weather events. Space- and ground-based geophysical observations allow us to capture the redistribution of surface loads in the form of water, ice, and sediments, as well as near-surface pressure and temperature changes in the atmosphere and varying fluid pressure in the shallow subsurface. While earthquakes are generally the result of tectonic or volcanic activity, the climatic forcings induce stress changes on faults that in some cases can be shown to significantly encourage or retard the occurrence of earthquakes, depending on the degree to which the external forces align with the background tectonic stress field. Stress changes associated with the emplacement and removal of km-thick ice sheets and lakes are large enough to substantially change slip- and earthquake rates on major plate-boundary faults and can also trigger events in largely aseismic continental interiors. However, climate-earthquake interactions are subtle and proving the interaction between climate and earthquakes requires careful mechanical modeling and statistical analysis. While investigations of earthquake weather and climate are not likely to be relevant for the characterization and mitigation of earthquake hazard, they provide important insights into the physical processes associated with lithospheric deformation, the earthquake cycle and frictional faulting in the Earth.