Temporary seismic monitoring of the Sulmona area (Abruzzo, Italy): quality study of microearthquake locations

Abstract

Abstract. Thanks to the installation of a temporary seismic network, a microseismicity study has been conducted in the Sulmona area (Abruzzo, Italy) with the aim of increasing the knowledge of seismogenic potential of existing active faults. In this work the first seven months (from 27 May to 31 December 2009) of recorded data have been analysed, over a total period of acquisition of about 30 months. Using a semi-automatic procedure, more than 800 local earthquakes has been detected, which highlight the background seismicity previously unknown. About 70% of these events have been relocated using a 1-D velocity model estimated specifically for the Sulmona area. Phase readings quality is checked and discussed, with respect to weighting schemes used by location algorithms, too. The integration of temporary network data with all the other data available in the region enable us to obtain a statistically more robust dataset of earthquake locations. Both the final hypocentral solutions and phase pickings are released as online Supplement. Local magnitude values of the newly detected events ranges between −1.5 and 3.7 and the completeness magnitude for the Sulmona area during the study period is about 1.1. Duration magnitude coefficients have been estimated as well, for comparison/integration purposes. Local Gutenberg–Richter relationship, estimated from the microseismic data, features low b value, possibly suggesting that the Sulmona area is currently undergoing high stress, in agreement with other recent studies. The time-space distribution of the seismic activity with respect to the known active faults, as well the seismogenic layer thickness, are preliminarily investigated.

Hydrogeochemical changes before and during the 2016 Amatrice-Norcia seismic sequence (central Italy)

“…1a,c ). This fault is considered as potentially responsible for past earthquakes of up to M w 6.5 or even stronger, and its last activation probably occurred during the 2 nd Century AD 35 , 57 – 59 . The Mt.…”

Coseismic Stress and Strain Field Changes Investigation Through 3‐D Finite Element Modeling of DInSAR and GPS Measurements and Geological/Seismological Data: The L'Aquila (Italy) 2009 Earthquake Case Study

“…In early‐instrumental and instrumental times, the Inner alignment was activated by the catastrophic Fucino 1915 earthquake ( M w 7.0) (Rovida et al, ), the Intermediate one by AQE 2009 ( M w 6.3) event, and the Outer one by a number of M w 5.0–5.5 events released during the 2009 L'Aquila sequence and by the major events of the 2016–2017 Central Italy seismic crisis. Moreover, minor sequences and background seismicity were distributed along patches of the other faults (Bagh et al, ; Boncio et al, , ; Chiarabba et al, ; Romano et al, ).…”

“…All the fault elements are represented as mesh surfaces, obtained through the Delauney triangulation algorithm (Caumon et al, ), which permits to accurately represent complex surface geometries. In some cases, the depth extrapolation was carried out from the surface trace with a fixed dip angle (50–60°); in the other cases, the depth interpretation was constrained with fault slip data (Ferrarini et al, ) and geological cross sections (Lavecchia et al, ), as well as with relocated sequences and/or minor seismicity with focal mechanism solutions (time interval from 1979 to 2015; Bagh et al, ; Boncio et al, ; Chiarabba et al, ; Chiaraluce et al, ; Romano et al, ). When available, the boreholes and the seismic reflection data were also used.…”

“…Updip, the fault segments are bounded by topographic digital elevation model data (20‐m resolution) and, laterally, one fault may terminate into another. Downdip, the faults are traced to reach the base of the seismogenic layer, as derived from the local sequences and minor seismicity (Bagh et al, ; Boncio et al, ; Chiarabba et al, ; Romano et al, ) and from relocated regional background seismicity in the time interval 2005–2012 (Chiarabba et al, ). The base of the seismological layer is interpreted as structurally controlled and coinciding with the LAED; the presence of this basal detachment is also highlighted by the seismicity distribution related to the 2016–2017 Central Italy seismic crisis (Bonini et al, ; INGV Working Group, ).…”

Ten Years of Geo-Archeo-Mythological Studies in the Abruzzo Region –Central Italy: An Updated Review

“…Geologic information on the geometric, kinematic, and energetic parameters of the major active faults in these areas defines discrete seismogenic structures (normal faults) of about 25-30 km in length [15], but many others remain poorly known, especially in the coastal area. In fact, the Majella area has a deep seismic source (thrust faults) extending towards the Adriatic coast with scarce evidence of superficial rupture but linked to destructive historical earthquakes (e.g., 1881-1882 Orsogna e Chieti, 1933 Taranta Peligna) [16,17].…”