Search results for "SEISMIC"
showing 10 items of 338 documents
Terremoto e architettura storica. Palermo e il sisma del 1726.
2015
On September 1st 1726 Palermo was hit by a violent earthquake. Although it did not bring about the destruction of the city, the earthquake caused widespread and extensive damage to the architectural heritage. The local insti- tutions carried out a series of actions involving representatives of the technical culture. These actions affected the subsequent appearance of the urban pattern and influenced the construction methods of the time. Crossing the data taken from chronicles of the time, from maps produced after the earthquake and above all copious archival documents, the research aims to reconstruct the state in which Palermo was after that tragic event, highlighting a number of aspects. …
Cluster analysis for cavity detection using seismic refraction and electrical resistivity tomography
2017
Geophysical methods (in particular ERT technique) constitute an excellent tool for the detection of buried cavities. However the integration approach of e different geophysical methods could minimize the ambiguity of geophysical interpretation of the buried cavity. The technique of electrical tomography has been joined to the technique of seismic refraction tomography in order to obtain more robust interpretations. Many tests have been carried out using synthetic data and experimental ones. It was finally used a statistical approach based on cluster analysis of the P-wave velocity, the density of the seismic rays and the electrical resistivity of the synthetic and experimental models. Distr…
A Strategy for the Prediction of the Response of Hysteretic Systems: A Base for Capacity Assessment of Buildings under Seismic Load
2014
A statistical non linearization method is used to approximate systems modeled by the Bouc differential equa- tion and excited by a Gaussian white noise external load. To this aim restricted potential models (RPM) are used, which are suitable for an extended number of nonlinear problems as have been proved several times. Since the solution of RPM is known by the probabilistic point of view, all statistical characteristics can be derived at once with advantages by the computational point of view. Hence, this paper discusses the possibility to determine sets of parameters characterizing po- tential models that are valid for describing a hysteretic behavior. In this way the characterization of …
Escalating CO2 degassing at the Pisciarelli fumarolic system, and implications for the ongoing Campi Flegrei unrest
2019
Abstract This short communication aims at providing an updated report on degassing activity and ground deformation variations observed during the ongoing (2012–2019) Campi Flegrei caldera unrest, with a particular focus on Pisciarelli, currently its most active fumarolic field. We show that the CO2 flux from the main Pisciarelli fumarolic vent (referred as “Soffione”) has increased by a factor > 3 since 2012, reaching in 2018–2019 levels (>600 tons/day) that are comparable to those typical of a medium-sized erupting arc volcano. A substantial widening of the degassing vents and bubbling pools, and a further increase in CO2 concentrations in ambient air (up to 6000 ppm), have also been detec…
Radon measurements in the SE and NE flank of Mt. Etna (Italy)
2007
Abstract Soil Radon has been monitored at two fixed sites located in the northeastern and southeastern flank of Mt. Etna. In this study we report the comparison between in-soil Radon concentration trend recorded in the SE flank and that one recorded in the NE one, where an in-soil Radon detection system is operating since 2001. The aim of this work was to implement the investigation area finding a suitable radon detection site, in the south-east flank of Mt. Etna, in order to better understand possible links between Radon anomalies and volcano dynamic. Radon data collected in NE and SE sites were compared with the volcanic tremor, frequency of occurrence of earthquakes and seismic strain-re…
Late Quaternary slip rates for the southern Elsinore fault in the Coyote Mountains, southern California from analysis of alluvial fan landforms and c…
2019
Abstract Offset alluvial fans along the Elsinore fault in the south-central Coyote Mountains were studied to resolve an average late Quaternary slip rate for this major western strand of the San Andreas fault system in southern California. Alluvial fans and their offsets were mapped using high-resolution DEMs combined with field observations of fan-surface morphology and the character of the soils developed in each fan remnant. Clast assemblage data was used to determine the source of each alluvial fan upstream of the fault, and U-series dating of pedogenic carbonate was used to estimate minimum ages of the alluvial fan surfaces. Forty U-Th dates on pedogenic carbonate confirm the utility o…
Recent Activity and Kinematics of the Bounding Faults of the Catanzaro Trough (Central Calabria, Italy): New Morphotectonic, Geodetic and Seismologic…
2021
A multidisciplinary work integrating structural, geodetic and seismological data was performed in the Catanzaro Trough (central Calabria, Italy) to define the seismotectonic setting of this area. The Catanzaro Trough is a structural depression transversal to the Calabrian Arc, lying in-between two longitudinal grabens: the Crati Basin to the north and the Mesima Basin to the south. The investigated area experienced some of the strongest historical earthquakes of Italy, whose seismogenic sources are still not well defined. We investigated and mapped the major WSW–ENE to WNW–ESE trending normal-oblique Lamezia-Catanzaro Fault System, bounding to the north the Catanzaro Trough. Morphotectonic …
Plio-Pleistocene geological evolution of the northern Sicily continental margin (southern Tyrrhenian Sea): new insights from high-resolution, multi-e…
2003
High-resolution seismic profiles were acquired in the north Sicily offshore region with an innovative, multi-tip sparker array which lacks ringing and has a base frequency around 600 Hz. The new data, combined with published data, suggest that intra-slope and extensional basins formed as a consequence of the late Miocene (?)–early Pliocene shortening and thrusting, and the middle (?)–late Pliocene continental rifting affecting the internal side of the Sicilian-Maghrebian chain. Early (?) Pleistocene to Holocene high-amplitude and high-frequency sea-level changes resulted in repeated sub-aerial exposure and flooding of the shelf, and the deposition of cyclically arranged hemipelagic and shel…
Integration of HVSR measures and stratigraphic constraints for seismic microzonation studies: the case of Oliveri (ME)
2014
Abstract. Because of its high seismic hazard the urban area of Oliveri has been subject of first level seismic microzonation. The town develops on a large coastal plain made of mixed fluvial/marine sediments, overlapping a complexly deformed substrate. In order to identify points on the area probably suffering relevant site effects and define a preliminary Vs subsurface model for the first level of microzonation, we performed 23 HVSR measurements. A clustering technique of continuous signals has been used to optimize the calculation of the HVSR curves. 42 reliable peaks of the H/V spectra in the frequency range 0.6–10 Hz have been identified. A second clustering technique has been applied t…
Spatial response spectra and site amplification effects
2002
A simplified analysis of local site amplification effects on the seismic response of multi-support structures is presented. The site effects are modeled by considering reflections and transmission of vertically propagating shear waves from bedrock to the surface through a soil layer. A random vibration-based response spectrum of a simple oscillator on two supports, one of which is founded on rock outcrop and the other on soil layer, is formulated in order to study the influence of non-uniform excitations on multi-support structures. Joint inertial and pseudo-static effects in the overall response are studied in detail. The resulting response spectra are formulated as displacement and force …