Large amplification of ground motion at rock sites within a fault zone in Nocera Umbra (central Italy)   总被引：2，自引：1，他引：1  

F. Marra  R. Azzara  F. Bellucci  A. Caserta  G. Cultrera  G. Mele  B. Palombo  A. Rovelli  E. Boschi 《Journal of Seismology》2000,4(4):543-554

During the two mainshocks of September 26, 1997 inthe Umbria-Marche border a strong-motion accelerographrecorded peak ground accelerations as large as 0.6 g,approximately, in the town of Nocera Umbra, atdistances of 10 to 15 km from the epicentres. Thisvalue is significantly larger than expected on thebasis of the usual regressions with magnitude anddistance. A broad-band amplification up to a factor of10 was consistently estimated in previous papers,using both weak and strong motion data recorded at theaccelerograph site during local moderate earthquakes.To study the cause of this amplification we deployedsix seismologic stations across the tectonic contactbetween the Ceno-Mesozoic limestone and the Mesozoicmarly sandstone where the accelerograph is installed.Seismograms of 21 shallow aftershocks in the magnituderange from 2.2 to 4.0 and a subcrustal M_w = 5.3event are analysed. Regardless of epicentre location,waveforms show a large complexity in an approximately200 m wide band adjacent to the tectonic contact. Thisis interpreted as the effect of trapped waves in thehighly fractured, lower velocity materials within thefault zone.  相似文献   

The sagging deep-seated gravitational movements on the eastern side of Mt. Amiata (Tuscany,Italy)     

Mauro Coltorti  Andrea Brogi  Lorenzo Fabbrini  Dario Firuzabadì  Lapo Pieranni 《Natural Hazards》2011,59(1):191-208

The eastern side of the Mt. Amiata volcano is affected by a series of deep-seated gravitational slope deformations (DsGSDs). The San Piero and the Podere Mezzavia DsGSDs affect the lower part of the slope. The main escarpments are located on the outer edges of the lava flows, but the landslides mostly affect the pre-volcanic Ligurian Terrains. A deeper movement, possibly exceeding 100 m in thickness, is evidenced by a long trench at the base of the main escarpment that indicates a sagging type movement. This deeper movement is responsible for the activation of a series of superficial rock and mud flows that show evidence of ongoing activity. The most likely location of the sliding surface is the tectonized contact between the Santa Fiora and Argille a Palombini Fms within the Ligurian units, although the superficial landslides prevent our determining with certainty if a clear-cut sliding surface already developed connecting the upper and the lower parts of the slope. These DsGSDs were activated along the flanks of a larger movement that affects the lava flow units cropping out in the middle slope of the volcano. A long main escarpment, secondary escarpments, trenches and borehole data suggest that the thickness could locally exceed 200 m and generate another sagging type movement. Up-slope and up-movement-facing counterscarps indicate the existence of a listric elongated spoon-shaped compound embryonic sliding surface. This sagging, which hosts the towns of Abbadia San Salvatore and Piancastagnaio, appears to be in a quiescent stage, according to preliminary monitoring with a global positioning system (GPS) network. The downcutting of the river network along the softer Pliocene terrains of the Radicofani basin is enhanced by the general uplift of the Apennines and seems to be the major factor in the activation of these DsGSDs.  相似文献   

The dependence of the melting temperatures of iron upon the choice of the interatomic potential     

E. Boschi  F. Mulargia  M. Bonafede 《Geophysical Journal International》1979,58(1):201-208

  相似文献   

Long-period toroidal earth free oscillations from the great Sumatra–Andaman earthquake observed by paired laser extensometers in Gran Sasso, Italy     

J. Park  A. Amoruso  L. Crescentini  E. Boschi 《Geophysical Journal International》2008,173(3):887-905

  相似文献   

A new dyke intrusion style for the Mount Etna May 2008 eruption modelled through continuous tilt and GPS data   总被引：2，自引：0，他引：2  

M. Aloisi  A. Bonaccorso  F. Cannavò  S. Gambino  M. Mattia  G. Puglisi  E. Boschi 《地学学报》2009,21(4):316-321

After a recharge phase that began in 2007, on 13 May 2008, a new eruption started on Mt. Etna volcano. The final intrusion was very fast, accompanied by a violent seismic swarm and marked by ground deformation recorded at permanent tilt and GPS stations. The violence of the eruptive event generated concern that the eruptive fissures might propagate downslope towards populated areas. The ground deformation modelling explains both the mechanism of the intrusion as well as the attempt of the dyke to propagate in the shallower part of the northern sector of the volcano. We show that the 2008 intrusion was characterized by a mechanism, which is new and different to the ones modelled in previous eruptions, following the path of the central conduit in the first part of the intrusion (below 1.6 km) and then breaking off towards the east in the last shallow part.  相似文献   

Global instability in the Ghil–Sellers model     

Tamás Bódai  Valerio Lucarini  Frank Lunkeit  Robert Boschi 《Climate Dynamics》2015,44(11-12):3361-3381

  相似文献   

Relationship between heavy metal accumulation and genetic variability decrease in the intertidal crab Pachygrapsus marmoratus (Decapoda; Grapsidae)     

Sara Fratini  Lorenzo Zane  Lapo Ragionieri  Marco Vannini  Stefano Cannicci   《Estuarine, Coastal and Shelf Science》2008,79(4):679-686

The “genetic erosion” hypothesis posits that heavy metal stress is related to a loss of genetic diversity at the population level. The genetic diversity of natural populations can, however, be affected by natural processes as well as by human impact. We studied the relationship between heavy metal bioaccumulation and genetic variability in the intertidal crab Pachygrapsus marmoratus. Tissue samples were collected from 40 individuals inhabiting four polluted and four unpolluted sites along the Tuscan coast (Mediterranean basin), and were examined for four heavy metals (arsenic, As, cadmium, Cd, lead, Pb, and copper, Cu). We also assessed the genetic variability of 235 crabs from the same localities using six microsatellite loci.Our results show that the bioaccumulation levels of these individuals accurately reflect the levels of pollution in their immediate environment, and that heavy metals accumulate more in the hepatopancreas than in the gills. Moreover, populations from polluted sites have significantly less genetic variability, measured as mean standardized d², and a significantly lower percentage of unrelated individuals, than populations from unpolluted sites. This evidence supports the “genetic erosion” hypothesis for metal heavy exposure in natural environments.  相似文献   

Lava flow hazard and risk at Mt. Cameroon volcano     

Massimiliano Favalli  Simone Tarquini  Paolo Papale  Alessandro Fornaciai  Enzo Boschi 《Bulletin of Volcanology》2012,74(2):423-439

Mt. Cameroon is one of the most active effusive volcanoes in Africa. About 500,000 people living or working around its fertile flanks are subject to significant threat from lava flow inundation. Lava flow hazard and risk were assessed by simulating probable lava flow paths using the DOWNFLOW code. The vent opening probability density function and lava flow length distribution were determined on the basis of available data from past eruptions at Mt. Cameroon volcano. Code calibration was performed through comparison with real lava flow paths. The topographic basis for simulations was the 90-m resolution SRTM DEM. Simulated lava flows from about 80,000 possible vents were used to produce a detailed lava flow hazard map. The lava flow risk in the area was mapped by combining the hazard map with digitized infrastructures (i.e., human settlements and roads). Results show that the risk of lava flow inundation is greatest in the most inhabited coastal areas comprising the town of Limbe, which constitutes the center of Cameroon’s oil industry and an important commercial port. Buea, the second most important town in the area, has a much lower risk although it is significantly closer to the summit of the volcano. Non-negligible risk characterizes many villages and most roads in the area surrounding the volcano. In addition to the conventional risk mapping described above, we also present (1) two reversed risk maps (one for buildings and one for roads), where each point on the volcano is classified according to the total damage expected as a consequence of vent opening at that point; (2) maps of the lava catchments for the two main towns of Limbe and Buea, illustrating the expected damage upon venting at any point in the catchment basin. The hazard and risk maps provided here represent valuable tools for both medium/long-term land-use planning and real-time volcanic risk management and decision making.  相似文献   

The generalization of the Mie—Grüneisen equation of state     

F. Mulargia  E. Boschi 《Geophysical Journal International》1978,55(1):263-267

Summary. A generalized Mie—Grüneisen equation of state is found without thermodynamical limits of validity. The range of applicability of the classical Mie—Grüneisen equation is discussed and results are presented of a particular case of the present equation. The various definitions of the Grüneisen's parameter are analysed in comparison with their generalized theoretical expression, given here.  相似文献   

A Representation Theorem in the Dynamic Theory of Porous Media     

E. Boschi  F. Mainardi 《Geophysical Journal International》1973,34(3):313-320

  相似文献