New Data to Study Possible Dependencies of Ground Shaking on Weather and Climate

In July 2021, the Geophysics Laboratory of our Department participated in an expedition in Argostoli, Cephalonia, with colleagues from CEA Cadarache (FR), the Institute of Engineering Seismology and Earthquake Engineering (ITSAK) and Ionian University, with the aim to install a meteorological station and a soil moisture meter in the proximity of the ARGONET seismological infrastructure. ARGONET is a vertical array of accelerometers (i.e. one accelerometer at the ground surface and four more inside boreholes, at various depths down to the engineering bedrock at ~83m), installed in Koutavos park, that has been providing us, on a 24/7 basis, with excellent earthquake data to be used in studies of soil behavior during strong shaking.

After the intense rainfalls of the past week, we checked the response of our newly added instrumentation and we got our first full record of rainfall height data and synchronous soil moisture levels in the shallow soil of ARGONET. At very shallow depth (e.g. 10cm) we do see the expected fast increase of soil moisture right after significant amounts of rain, but also the slower moisture unloading between rainfall episodes as shallow soil dries out. At larger depth (e.g. 75cm), soil moisture levels rise less rapidly and after larger amounts of rainfall, but moisture remains elevated for a longer period.

Meteorological and soil moisture data from ARGONET keep coming in real-time and we are looking forward to combining them with earthquake data to further study how differently soil behaves during earthquake shaking depending on the amount of water contained in it. Will it make a difference during a strong earthquake if the soil is wet or dry? And how big can this difference be? Can it be large enough to increase (or decrease) the impact of an earthquake? More on this on future posts.

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