Analysis of background seismicity recorded at Mefite d’Ansato CO2 emission field in the framework of FURTHER project: first results.

Abstract

<p>FURTHER – “The role of FlUids in the pReparaTory pHase of EaRthquakes in Southern Apennines” is an INGV Departement Strategic Project devoted to define the role of fluids in earthquake genesis. One of the target areas of the multidisciplinary study is Mefite d’Ansanto, which is the largest area of non-volcanic low temperature CO<sub>2</sub> emission field on the Earth. In particular, Work Package 1.4 is dedicated to the application of analysis methodologies in time and frequency domains, aimed to intercept eventual variations in fluid behavior before or in correspondence of local and regional earthquakes, using recordings from the INGV National Seismic Network (IV) and local networks. For this purpose, temporary acquisition surveys have been locally deployed.</p><p>On November 20, 2020, a stand-alone seismic station equipped with a Guralp CMG40T 60s broadband sensor, was installed close to the Mefite emission field. In this study we analyze some characteristics of the local seismicity, e.g., frequency content, energy temporal pattern (RMS) and polarization (Montalbetti et al., 1970), and estimate site effects (Nakamura, 1989; http://www.geopsy.org/). Here we present the first results of the ongoing investigation of the seismic noise wavefield in the Mefite area. The temporal pattern of the retrieved seismological observables is compared with the meteorological parameters, such as temperature and rainfall, to find possible relationships with exogenous factors.</p><p>Preliminary analysis of the waveforms acquired by the stations of the (IV) have been also performed. We selected the stations inside a radius of 30 km from Mefite area to eventually retrieve  the fluid dynamics footprint in the recorded wavefield.</p><p>The identification of the wavefield and site characteristics will be useful to define the features of the next survey planned in the area.</p><p> </p><p>References</p><p>Montalbetti, J. R., Kanasevich, E. R. (1970): Enhancement of teleseismic body phase with a polarization filter. Geophys. J. Int. 21 (2), 119–129.</p><p>Nakamura, Y. (1989). A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface, Railway Technical Research Institute, Quarterly Reports, 30 (1), 25-33.</p>

One-Year Seismic Survey of the Tectonic CO2-Rich Site of Mefite d’Ansanto (Southern Italy): Preliminary Insights in the Seismic Noise Wavefield

“…FURTHER (the role of FlUids in the pReparaTory pHase of EaRthquakes in Southern Apennines, , last access 28 November 2022) is a multidisciplinary Departmental Strategic Project of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) started in 2020 to investigate the involvement of fluids in the seismogenesis of the southern Apennines, Italy. One of the goals of the project is to detect the footprint of fluid contribution to the seismogenic process in the seismic signal recorded at Mefite d’Ansanto [ 22 ]. In the present work, we describe the seismic survey carried out at Mefite from September 2020 to September 2021 and present a first insight in the local seismic wavefield properties throughout the inspection of the temporal patterns and the spectral characteristics of the continuous seismic noise signals.…”