Detailed crustal structure in the area of the southern Apennines–Calabrian Arc border from local earthquake tomography

Totaro, Cristina; Koulakov, Ivan; Orecchio, B.; Presti, Debora

doi:10.1016/j.jog.2014.07.004

Cited by 32 publications

(33 citation statements)

References 60 publications

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“…Infiltration of fluids may also cause an expansion of the focal area due to an incremental stress accumulation leading to larger ruptures (Hainzl & Fischer 2002). The presence of fluids in the Pollino shallower crust down to 10 km is consistent with the large scale v p /v s anomaly (Barberi et al 2004;Totaro et al 2014), with the low geothermal gradient (Della Vedova et al 2001), electro-magnetic signals associated to the seismic sequence (Balasco et al 2014), and variation in time of the v p /v s ratio throughout the seismic sequence (Piccinini et al 2014 submitted to BGTA).…”

Section: Discussionsupporting

confidence: 54%

“…The anomaly seems to disappear at depths of 10-20 km and it appears again in the 20-30 km layer. A recently published crustal tomographic investigation also using the events of the 2010-2013 swarm sequence found an even larger volume with a prounanced v p /v s anomaly in the shallowest 10 km of the crust (Totaro et al 2014). This is broadly interpreted by invoking high crack density, presence of fluids or porous rocks filled by fluids (Barberi et al 2004;Totaro et al 2014).…”

Section: Tectonic Setting Of the Pollino Range Southern Italymentioning

confidence: 95%

“…A recently published crustal tomographic investigation also using the events of the 2010-2013 swarm sequence found an even larger volume with a prounanced v p /v s anomaly in the shallowest 10 km of the crust (Totaro et al 2014). This is broadly interpreted by invoking high crack density, presence of fluids or porous rocks filled by fluids (Barberi et al 2004;Totaro et al 2014). The presence of fluid circulation in terms of deep meteoric water infiltration underneath the Pollino range is also invoked to explain the anomalously low geothermal gradient of the region (Della Vedova et al 2001).…”

Section: Tectonic Setting Of the Pollino Range Southern Italymentioning

confidence: 95%

“…Only a few tomographic studies have been carried out so far in the Pollino area (Barberi et al 2004;Orecchio et al 2011;Totaro et al 2014). Barberi et al (2004) performed a seismic tomographic inversion for v p and the v p /v s ratio using natural earthquakes and artificial sources in 10 km crustal layers down to 40 km depth.…”

Section: Tectonic Setting Of the Pollino Range Southern Italymentioning

confidence: 99%

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Aseismic transient driving the swarm-like seismic sequence in the Pollino range, Southern Italy

Passarelli¹,

Hainzl²,

Cesca³

et al. 2015

Geophysical Journal International

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S U M M A R YTectonic earthquake swarms challenge our understanding of earthquake processes since it is difficult to link observations to the underlying physical mechanisms and to assess the hazard they pose. Transient forcing is thought to initiate and drive the spatio-temporal release of energy during swarms. The nature of the transient forcing may vary across sequences and range from aseismic creeping or transient slip to diffusion of pore pressure pulses to fluid redistribution and migration within the seismogenic crust. Distinguishing between such forcing mechanisms may be critical to reduce epistemic uncertainties in the assessment of hazard due to seismic swarms, because it can provide information on the frequency-magnitude distribution of the earthquakes (often deviating from the assumed Gutenberg-Richter relation) and on the expected source parameters influencing the ground motion (for example the stress drop). Here we study the ongoing Pollino range (Southern Italy) seismic swarm, a long-lasting seismic sequence with more than five thousand events recorded and located since October 2010. The two largest shocks (magnitude M w = 4.2 and M w = 5.1) are among the largest earthquakes ever recorded in an area which represents a seismic gap in the Italian historical earthquake catalogue. We investigate the geometrical, mechanical and statistical characteristics of the largest earthquakes and of the entire swarm. We calculate the focal mechanisms of the M l > 3 events in the sequence and the transfer of Coulomb stress on nearby known faults and analyse the statistics of the earthquake catalogue. We find that only 25 per cent of the earthquakes in the sequence can be explained as aftershocks, and the remaining 75 per cent may be attributed to a transient forcing. The b-values change in time throughout the sequence, with low b-values correlated with the period of highest rate of activity and with the occurrence of the largest shock. In the light of recent studies on the palaeoseismic and historical activity in the Pollino area, we identify two scenarios consistent with the observations and our analysis: This and past seismic swarms may have been 'passive' features, with small fault patches failing on largely locked faults, or may have been accompanied by an 'active', largely aseismic, release of a large portion of the accumulated tectonic strain. Those scenarios have very different implications for the seismic hazard of the area.

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Section: Discussionsupporting

confidence: 54%

Section: Tectonic Setting Of the Pollino Range Southern Italymentioning

confidence: 95%

Section: Tectonic Setting Of the Pollino Range Southern Italymentioning

confidence: 95%

Section: Tectonic Setting Of the Pollino Range Southern Italymentioning

confidence: 99%

See 2 more Smart Citations

Aseismic transient driving the swarm-like seismic sequence in the Pollino range, Southern Italy

Passarelli¹,

Hainzl²,

Cesca³

et al. 2015

Geophysical Journal International

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“…Space‐time evolution of the rollback process, that since Upper Pliocene appeared mainly confined in the Calabrian Arc area, can be referred to progressive variation of lithosphere that approaches the retreating trench. In particular, remarkable structural differences characterize the Ionian tectonic unit and the bordering ones of Sicily and Southern Apennines [ Catalano et al , ; Lucente and Speranza , ; Barberi et al , ; Orecchio et al , ; Totaro et al , ]. Several geodynamic features of the study region (such as microplate boundaries and kinematics) are still uncertain [see, e.g., Jenny et al , ; Nocquet , ].…”

Section: Geodynamic Settingsmentioning

confidence: 99%

Seismogenic stress field estimation in the Calabrian Arc region (south Italy) from a Bayesian approach

Totaro

Orecchio

Presti

et al. 2016

Geophysical Research Letters

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A new high‐quality waveform inversion focal mechanism database of the Calabrian Arc region has been compiled by integrating 292 mechanisms selected from literature and catalogs with 146 newly computed solutions. The new database has then been used for computation of posterior density distributions of stress tensor components by a Bayesian method never applied in south Italy before the present study. The application of this method to the enhanced database has allowed us to provide a detailed picture of seismotectonic stress regimes in this very complex area where lithospheric unit configuration and geodynamic engines are still strongly debated. Our results well constrain the extensional domain of Calabrian Arc and the compressional one of the southernmost Tyrrhenian Sea. In addition, previously undetected transcurrent regimes have been identified in the Ionian offshore. The new information released here will furnish useful tools and constraints for future geodynamic investigations.

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Estimating Stability and Resolution of Waveform Inversion Focal Mechanisms

Scolaro

Totaro

Presti

et al. 2018

Moment Tensor Solutions

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Detailed crustal structure in the area of the southern Apennines–Calabrian Arc border from local earthquake tomography

Cited by 32 publications

References 60 publications

Aseismic transient driving the swarm-like seismic sequence in the Pollino range, Southern Italy

Aseismic transient driving the swarm-like seismic sequence in the Pollino range, Southern Italy

Seismogenic stress field estimation in the Calabrian Arc region (south Italy) from a Bayesian approach

Estimating Stability and Resolution of Waveform Inversion Focal Mechanisms

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