Search results for "Seismicity"
showing 10 items of 56 documents
Fluid-triggered earthquake swarms in the Rwenzori region, East African Rift—Evidence for rift initiation
2012
The Rwenzori Mountains are located within the Albertine Rift Valley in western Uganda. To monitor the microseismic activity in the area we have deployed a seismic network of up to 35 stations for a period of about 20 months. The analysis of the recordings revealed several earthquake clusters within a restricted area NE of the mountain block. The clusters form elongated pipes with 1–2 km diameter and vertical extensions of 3–5 km. Most of them are located in 5–16 km depths; however one cluster reaches down to 22 km. Each cluster is composed of a series of single earthquake swarms with durations between a few days and more than a week, interrupted by intervals of inactivity of up to several m…
Crustal Structure of the Seismogenic Volume of the 2010–2014 Pollino (Italy) Seismic Sequence From 3D P- and S-Wave Tomographic Images
2021
A tomographic analysis of Mt. Pollino area (Italy) has been performed using earthquakes recorded in the area during an intense seismic sequence that occurred between 2010 and 2014. 870 local earthquakes with magnitude ranging from 1.8 to 5.0 were selected considering the number of recording stations, the signal quality, and the hypocenter distribution. P- and S-wave arrival times were manually picked and used to compute 3D velocity models through tomographic seismic inversion. The resulting 3D distributions of VP and VS are characterized by high resolution in the central part of the investigated area and from surface to about 10 km below sea level. The aim of the work is to obtain high-qual…
Interaction between seismicity and deformation on different time scales in volcanic areas: Campi Flegrei and Stromboli
2019
We study oscillations recorded at Stromboli and Campi Flegrei by different sensors: seismometers, strainmeters and tiltmeters. We examine both the high-frequency (>0.5 Hz) portion of the spectrum and very long period signals up to tidal scales. In this context, seismicity and deformation are investigated on different time scales (from minutes to days/years) in order to identify the basic elements of their interaction, whose understanding should provide new insights on the predictive models. In this work, the strict relation of tides and volcanic processes is shown. At Stromboli, indeed the transition from the stationary phase to the non-stationary phase seems to have a tidal precu…
Integration of onshore and offshore seismic arrays to study the seismicity of the Calabrian Region: a two steps automatic procedure for the identific…
2014
Abstract. We plan to deploy in the Taranto Gulf some Ocean Bottom broadband Seismometer with Hydrophones. Our aim is to investigate the offshore seismicity of the Sibari Gulf. The seismographic network optimization consists in the identification of the optimal sites for the installation of the offshore stations, which is a crucial factor for the success of the monitoring campaign. In this paper, we propose a two steps automatic procedure for the identification of the best stations geometry. In the first step, based on the application of a set of a priori criteria, the suitable sites to host the ocean bottom seismic stations are identified. In the second step, the network improvement is eval…
Monochromatic Long-Period Seismicity Prior to the 2012 Earthquake Swarm at Little Sitkin Volcano, Alaska
2021
Detection of the earliest stages of unrest is one of the most challenging and yet critically needed aspects of volcano monitoring. We investigate a sequence of five unusual long-period (LP) earthquakes that occurred in the days prior to the onset of a months-long volcano-tectonic (VT) earthquake swarm beneath Little Sitkin volcano in the Aleutian Islands during late 2012. The long-period earthquakes had two distinctive characteristics: their signals were dominated by a monochromatic spectral peak at approximately 0.57 Hz and they had impulsive P and S-wave arrivals on a seismometer located on Amchitka Island 80 km to the southeast of the volcano. In each case, the monochromatic earthquakes …
Structural architecture and active deformation pattern in the northern sector of the Aeolian-Tindari-Letojanni fault system (SE Tyrrhenian Sea-NE Sic…
2017
Framed in the current geodynamics of the central Mediterranean, the Aeolian-Tindari-Letojanni fault system is part of a wider NW-SE oriented right-lateral wrench zone which accommodates diverging motion between regional-scale blocks located at the southern edge of the Calabrian Arc. In order to investigate the structural architecture and the active deformation pattern of the northern sector of this tectonic feature, structural observations on-land, high and very-high resolution seismic reflection data, swath bathymetry data and seismological and geodetic data were merged from the Lipari-Vulcano volcanic complex (central sector of the Aeolian Islands) to the Peloritani Mountains across the G…
PROCESSI ATTIVI NEL MARGINE CONTINENTALE DELLA SICILIA NORD-OCCIDENTALE: NEOTETTONICA, RISALITA DI FLUIDI E FENOMENI GRAVITATIVI
2014
La ricerca riguarda l’analisi degli elementi morfostrutturali, le strutture legate alle emissioni di fluidi ed i fenomeni di trasporto sia gravitativo che selettivo, in ambiente sommerso ed emerso, presenti nel settore del margine continentale nord-siciliano compreso tra i meridiani passanti per le isole Egadi e Cefalù, al fine di ottenere un modello evolutivo durante il Quaternario. In particolare sono stati studiati in dettaglio: a) gli elementi morfostrutturali, al fine di ottenere informazioni sull’evoluzione recente dell’area, concentrando l’attenzione sulle faglie recenti e attive, integrando anche le informazioni concernenti la sismicità dell’area, ricavati dai database online; b) le…
GIS-based seismic shaking slope vulnerability map of Sicily (Central Mediterranean
2010
Evidence of Roman Earthquake Surface Faulting at Santa Venera al Pozzo (Catania, Southern Italy): a probable seismic event in 251 AD?
2018
The record of historical seismicity of Catania (Southern Italy) and its neighbourhood during the first millennium AD is largely incomplete due to the scarcity of sources reporting information on earthquake damage, whereas on the contrary numerous historical sources provide plentiful description of past Etnean eruptions affecting the Catania area. This study provides new insights on the Catania seismic history, which was struck by large earthquakes during its recent history (e.g. 1169, 1542, 1693, 1818 earthquakes). During the first millennium, the only documented earthquake occurred in 251 AD, a year before of the big Etna eruption of 252 AD (Guidoboni et al., 2014). This earthquake left we…