429 research outputs found

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

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    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

    Hydrological anomalies connected to earthquakes in southern Apennines (Italy)

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    The study of hydrological variations in the watersheds of seismic areas can be useful in order to acquire a new knowledge of the mechanisms by which earthquakes can produce hydrological anomalies. Italy has the availability of many long historical series both of hydrological parameters and of seismological data, and is an ideal laboratory to verify the validity of theoretical models proposed by various authors. In this work we analyse the hydrological anomalies associated with some of the big earthquakes that occurred in the last century in the southern Apennines: 1930, 1980 and 1984. For these earthquakes we analysed hydrometric and pluviometric data looking for significant anomalies in springs, water wells and mountain streams. The influence of rainfalls on the normal flows of rivers, springs and wells has been ascertained. Also, the earthquake of 1805, for which a lot of hydrological perturbations have been reported, is considered in order to point out effects imputable to this earthquake that can be similar to the effects of the other big earthquakes. The considered seismic events exhibit different modes of energy release, different focal mechanisms and different propagation of effects on the invested areas. Furthermore, even if their epicentres were not localised in contiguous seismogenetic areas, it seems that the hydrological effects imputable to them took place in the same areas. Such phenomena have been compared with macroseismic fields and transformed in parameters, in order to derive empirical relationships between the dimensions of the event and the characteristics of the hydrological variations. The results of this work point to a close dependence among hydrological anomalies, regional structures and fault mechanisms, and indicate that many clear anomalies have been forerunners of earthquakes. In 1993, the Naples Bureau of the Hydrographic National Service started the continuous monitoring of hydrologic parameters by a network of automatic stations and transmission in real time; presently 7 acquifers are under control in which also pH, <i>T</i> , salinity, electrical conductivity, dissolved oxygen are measured. We envisage to increase the number of monitoring sites and controlled parameters

    Liposomal amphotericin B for visceral leishmaniasis in human immunodeficiency virus-coinfected patients: 2-year treatment outcomes in Bihar, India

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    Reports on treatment outcomes of visceral leishmaniasis (VL)-human immunodeficiency virus (HIV) coinfection in India are lacking. To our knowledge, none have studied the efficacy of liposomal amphotericin B in VL-HIV coinfection. We report the 2-year treatment outcomes of VL-HIV-coinfected patients treated with liposomal amphotericin B followed by combination antiretroviral treatment (cART) in Bihar, India

    Radon in active volcanic areas of southern Italy

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    The radiogenic gas radon is considered a valid precursor of events like eruptions and earthquakes. We are monitoring the variations in time of this gas in soils and in waters of many active volcanic areas of Southern Italy. The greatest differences in Rn content of the investigated volcanic areas are: Ischia and Campi Flegrei have more Rn than Vesuvio and Vulcano, both in soils and in waters. The thermalized waters of Ischia are enriched in Rn 15 times with respect to soils, while in the other areas soils and underground waters have comparable Rn contents
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