THE 23 JULY 1930 EARTHQUAKE (MS=6.7) IN THE SOUTHERN APENNINES (ITALY): GEOLOGICAL AND HYDROLOGICAL EFFECTS

Tranfaglia, G. and Esposito, E. and Porfido, S. and Pece, R. (2011) THE 23 JULY 1930 EARTHQUAKE (MS=6.7) IN THE SOUTHERN APENNINES (ITALY): GEOLOGICAL AND HYDROLOGICAL EFFECTS. Bollettino Geofisico ( n. 1-). pp. 63-86.

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Abstract

The 23 July 1930 earthquake (MS=6.7) in the Southern Apennines (Italy) was a catastrophic event that produced many effects such as surface faulting, fractures, landslides, settlements, hydrological changes, variations in chemical/ physical activity related to the volcanic and/or thermal zones and also acoustic and optical phenomena. It is the first great earthquake of the twentieth century that was studied, thanks to the hydrological monitoring network of the Italian Hydrographic Survey (IHS) set up from 1925 to 1929. For this earthquake we analysed the initial IHS hydrometric and pluviometric data, looking for significant anomalies in springs, water wells and mountain streams. Hydrological data relative to rivers, springs and water wells indicate that some changes can be correlated with the earthquake: a post-seismic excess discharge in some streams, pre- and co-seismic decreases in stream flows and water levels in wells, pre- and post-seismic increases in discharges. The pre- and co-seismic stresses and the tectonic deformations were studied in order to find a possible model of interaction between stress state and hydrological variations. The anomalies found in this work can be considered “rebound anomalies”, which are the most common precursor reported by several authors and related to increases in porosity and permeability caused by the fracturing that precedes an earthquake. An estimation of the total excess discharge (0.035 km3) caused by the Ms=6.7 Irpinia earthquake is consistent with the excess discharge of about 0.01 km3 determined for the Mw=6.9 Loma Prieta earthquake. To define the normal hydrodynamic behaviour of the considered aquifers, an analysis of the correlation between rainfalls and water levels and flow rates has been carried out. The delay of significant peaks in the correlograms of figure 7 with respect to the start of the hydrological anomaly and/or its duration, can define the space-time limits of the changes correlated with earthquake.

Item Type: Article
Uncontrolled Keywords: 1930 Irpinia earthquake, geological effects, hydrological variations, southern Apennines, Esi 2007 intensities
Subjects: 500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia > 551.2 Vulcani, terremoti, acque termali e gas > 551.22 Terremoti (Classificare qui la Sismologia) (Classificare le onde di maremoto in 551.463) > 551.220287 Terremoti - Prove e misure (Classificare qui la Sismografia)
500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia > 551.2 Vulcani, terremoti, acque termali e gas > 551.23 Acque termali e gas (Include i materiali vulcanici volatili) (Classificare qui le manifestazioni superficiali, p.e., fumarole, sorgenti calde)
Depositing User: dr Sabina Porfido
Date Deposited: 05 Jan 2012 09:56
Last Modified: 26 Jan 2012 09:00
URI: http://eprints.bice.rm.cnr.it/id/eprint/3839

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