The study's aim is constraining the source characteristics of the Casamicciola Terme active and capable fault system at Ischia Island for providing a contribution to the local seismic hazard. Ischia is an active volcanic island on the NW side of the Gulf of Naples and belongs to the Campanian volcanic province. On August 21st 2017 a Md 4.0, 1,5 km depth volcanotectonic earthquake reactivated the Casamicciola Terme capable fault. The epicentral location of the relevant earthquake in the last three centuries, in particular the ones of 1796, 1828, 1881, and 1883, are systematically confined within few km2 in Casamicciola Terme area. Here, a clear stratigraphic and morphological trace is preserved and represented by the graben at the base of the N flank of Mt Epomeo, which formed as the result of Holocene extensional tectonic deformation. The Mt. Epomeo (787 m a.s.l.) uplift is the final stage of the resurgence phase that created the main morphological structure emerging nowadays, with an average rate of ca. 3 cm/yr in the last 30 kyr. The Mt. Epomeo is clearly asymmetric, with a maximum displacement on the N flank linked to an E-W normal fault system where all the significant seismic activity is centered. The MACFI project consist of a multidisciplinary approach, including: i) a geophysical survey of the 2017 earthquake epicentral area by 3D Deep Electrical Resistivity Tomography with three ERT profiles across the Casamicciola Terme graben; ii) a drone aerial survey with a LiDAR (Light Detection and Ranging) scanner generating a 5-10 cm resolution DTM, and a radiometric thermal camera areas, for identifying the morphological and thermal signature of faulting and progressive offset along primary surface ruptures along the southern portion of the Holocene graben; iii) the occurrence of directional amplification effects as an effect of the fault activity and rock fracturing at depth. The combined aerial LiDAR and thermal remote sensing by drone allow to map with unprecedented precision the surface traces of the main and minor faults and fractures along the southern portion of the Holocene graben, and to identify possible correlations with the ascent of geothermal fluids.
Multidisciplinary Approach for Capable Fault system study at Ischia Island, northern sector of Mt Epomeo (MACFI project): preliminary results
2023
Abstract
The study's aim is constraining the source characteristics of the Casamicciola Terme active and capable fault system at Ischia Island for providing a contribution to the local seismic hazard. Ischia is an active volcanic island on the NW side of the Gulf of Naples and belongs to the Campanian volcanic province. On August 21st 2017 a Md 4.0, 1,5 km depth volcanotectonic earthquake reactivated the Casamicciola Terme capable fault. The epicentral location of the relevant earthquake in the last three centuries, in particular the ones of 1796, 1828, 1881, and 1883, are systematically confined within few km2 in Casamicciola Terme area. Here, a clear stratigraphic and morphological trace is preserved and represented by the graben at the base of the N flank of Mt Epomeo, which formed as the result of Holocene extensional tectonic deformation. The Mt. Epomeo (787 m a.s.l.) uplift is the final stage of the resurgence phase that created the main morphological structure emerging nowadays, with an average rate of ca. 3 cm/yr in the last 30 kyr. The Mt. Epomeo is clearly asymmetric, with a maximum displacement on the N flank linked to an E-W normal fault system where all the significant seismic activity is centered. The MACFI project consist of a multidisciplinary approach, including: i) a geophysical survey of the 2017 earthquake epicentral area by 3D Deep Electrical Resistivity Tomography with three ERT profiles across the Casamicciola Terme graben; ii) a drone aerial survey with a LiDAR (Light Detection and Ranging) scanner generating a 5-10 cm resolution DTM, and a radiometric thermal camera areas, for identifying the morphological and thermal signature of faulting and progressive offset along primary surface ruptures along the southern portion of the Holocene graben; iii) the occurrence of directional amplification effects as an effect of the fault activity and rock fracturing at depth. The combined aerial LiDAR and thermal remote sensing by drone allow to map with unprecedented precision the surface traces of the main and minor faults and fractures along the southern portion of the Holocene graben, and to identify possible correlations with the ascent of geothermal fluids.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
