Publication Date:
2021-08-30
Description:
Seismological data recorded in the Ionian Sea by a network of seven Ocean Bottom
Seismometers (OBSs) during the 2017–2018 SEISMOFAULTS experiment provides a
close-up view of seismogenic structures that are potential sources of medium-high
magnitude earthquakes. The high-quality signal-to-noise ratio waveforms are observed
for earthquakes at different scales: teleseismic, regional, and local earthquakes as well as
single station earthquakes and small crack events. In this work, we focus on two different
types of recording: 1) local earthquakes and 2) Short Duration Events (SDE) associated to
micro-fracturing processes. During the SEISMOFAULTS experiment, 133 local
earthquakes were recorded by both OBSs and land stations (local magnitude ranging
between 0.9 and 3.8), while a group of local earthquakes (76), due to their low magnitude,
were recorded only by the OBS network. We relocated 133 earthquakes by integrating
onshore and offshore travel times and obtaining a significant improvement in accuracy,
particularly for the offshore events. Moreover, the higher signal-to-noise ratio of the OBS
network revealed a significant seismicity not detected onshore, which shed new light on
the location and kinematics of seismogenic structures in the Calabrian Arc accretionary
prism and associated to the subduction of the Ionian lithosphere beneath the Apennines.
Other signals recorded only by the OBS network include a high number of Short Duration
Events (SDE). The different waveforms of SDEs at two groups of OBSs and the close
correlation between the occurrence of events recorded at single stations and SDEs
suggest an endogenous fluid venting from mud volcanoes and active fault traces. Results
from the analysis of seismological data collected during the SEISMOFAULTS experiment
confirm the necessity and potential of marine studies with OBSs, particularly in those
geologically active areas of the Mediterranean Sea prone to high seismic risk.
Description:
Published
Description:
661311
Description:
3A. Geofisica marina e osservazioni multiparametriche a fondo mare
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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