Coseismic and postseismic displacements related with the 1997 Earthquake Sequence in Umbria‐Marche (Central Italy)

Basili, Roberto; Meghraoui, Mustapha

doi:10.1029/2000gl012102

Cited by 26 publications

(39 citation statements)

References 18 publications

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“…Focal mechanisms of the main shocks which occurred in 1997 (as well as 1979 and 1984), also confirmed by stress indicators (MONTONE et al, 1997), highlighted active extension processes in the NE-SW and E-W directions . The entire seismogenic process caused crustal deformation with a maximum horizontal co-seismic displacement of 14 ± 1.8 cm and a maximum co-seismic subsidence of 24 ± 3 cm detected by means of SAR differential interferometry and GPS data (STRAMONDO et al, 1999), while a post-seismic long-term deformation process was detected by means of levelling data (BASILI and MEGHRAOUI, 2001). Starting from the beginning of the seismic crisis (September 26, 1997), samples of thermal waters (Bagni di Triponzo, Parrano and Stifone) and gas vents (Montecastello Table 2 CO 2 output from degassing areas, wells and vents of Central Apennines.…”

Section: The Fluids Geochemistry and The Co 2 Output During The Seismmentioning

confidence: 99%

CO2 Degassing over Seismic Areas: The Role of Mechanochemical Production at the Study Case of Central Apennines

Italiano

Martinelli

Plescia

2008

Pure appl. geophys.

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Field observations coupled with experimental results show that CO 2 can be produced by mechanical energy applied to carbonate rocks becoming an unexpected additional gas source besides that degassed from the mantle or produced by thermometamorphism. The evidence that a large amount of carbon dioxide associated with radiogenic-type helium (R/Ra as low as 0.01-0.08) is released through continental areas, denotes the absence of a contribution from the mantle or from mantle-derived fluids. Data collected during the seismic crisis which struck the Central Apennines in 1997-98 have shown an enhanced CO 2 flux not associated with the presence of mantle or thermometamorphic-derived fluids. On the other hand, new experimental results highlight the possibility of producing CO 2 by mechanical energy that acts on the calcite crystalline lattice. While the CO 2 released over the geothermal areas (e.g., Larderello Geothermal Field) is obviously derived by mantlederived activities, this is not the case of the huge amount of CO 2 released over the seismically active areas where the presence mantle-derived products is ruled out. We propose that mechanical energy, e.g., released during seismic events, microseismicity or creeping processes is a possible additional energy source able to produce CO 2 and thus could explain the presence of CO 2 degassing over tectonic areas where the influence of the mantle is low.

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Section: The Fluids Geochemistry and The Co 2 Output During The Seismmentioning

confidence: 99%

CO2 Degassing over Seismic Areas: The Role of Mechanochemical Production at the Study Case of Central Apennines

Italiano

Martinelli

Plescia

2008

Pure appl. geophys.

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“…5), in contrast to the increase in the values recorded at all the cold and thermal waters. Such divergent behaviour, observed both in coincidence with the 1997 and 1998 seismic events and among the various sampling sites, might be related to the different permeability variations induced by the faulting activity, which was clearly extensive during the 1997 event (Basili and Meghraoui 2001) but compressive in March, 1998 (Morelli et al 2000).…”

Section: Temporal Variationsmentioning

confidence: 99%

Geochemical Monitoring of Cold Waters during Seismicity: Implications for Earthquake-induced Modification in Shallow Aquifers

Italiano¹,

Caracausi²,

Favara³

et al. 2005

Terr. Atmos. Ocean. Sci.

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The geochemical monitoring carried out on fluids released in the Central Apennines (Umbria region) evidenced seismically-induced modifications of the physic-chemical parameters in all the released fluids, including some cold waters circulating in certain carbonate rocks that are exploited for drinking purposes. The results allowed us to recognize the presence of components of diverse origin that changed the chemical composition of the water. These components, potentially dangerous for human consumption, can be considered as being "secondary effects" on local aquifers, induced by crustal deformation.We would also stress the relationship between the circulating fluids and active tectonic structures, as we detected modifications in some springs that were apparently not located anywhere near the local faults. The temporal variations in the geochemical features of the investigated cold waters are related to the local faulting activity that occurs during seismogenesis. The geochemical monitoring that provided information on fault movements during the seismic crisis, is also able to give us information regarding faulting activity in its earlier stages.

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“…These findings represent evidence for horizontal postseismic deformation triggered by shallow earthquakes, in the Mediterranean region, as first shown in Aoudia et al (2003). For normal faulting, these applications show the relevance of source depth with respect to thickness and the Figure 44 2002-1999 baseline length variations along the GPS section with respect to the A 0 site using GIPSY and Bernese solutions, gray and black vertical bars, respectively, versus viscoelastic model predictions for FM1 (Salvi et al, 2000), FM2 (Zollo et al, 1999), and FM3 (Basili and Meghraoui, 2001), using a viscosity of 10 18 and 10 17 Pa s for the TZ and lower crust, respectively. Fine rheological layering in the crust has a major role in the interplay of relaxation in the TZ and LC with respect to relaxation in the mantle when shallow sources are considered in normal-mode relaxation theory.…”

Section: Postseismic Deformation From Shallow Earthquakesmentioning

confidence: 83%

Plate Deformation

Sabadini

2015

Treatise on Geophysics

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Coseismic and postseismic displacements related with the 1997 Earthquake Sequence in Umbria‐Marche (Central Italy)

Cited by 26 publications

References 18 publications

CO2 Degassing over Seismic Areas: The Role of Mechanochemical Production at the Study Case of Central Apennines

CO2 Degassing over Seismic Areas: The Role of Mechanochemical Production at the Study Case of Central Apennines

Geochemical Monitoring of Cold Waters during Seismicity: Implications for Earthquake-induced Modification in Shallow Aquifers

Plate Deformation

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