Search results for "crustal structure"

The formation of peak rings in large impact craters.

2016

The Chicxulub impact crater, known for its link to the demise of the dinosaurs, also provides an opportunity to study rocks from a large impact structure. Large impact craters have “peak rings” that define a complex crater morphology. Morgan et al. looked at rocks from a drilling expedition through the peak rings of the Chicxulub impact crater (see the Perspective by Barton). The drill cores have features consistent with a model that postulates that a single over-heightened central peak collapsed into the multiple-peak-ring structure. The validity of this model has implications for far-ranging subjects, from how giant impacts alter the climate on Earth to the morphology of crater-dominated …

NEW INSIGHTS INTO THE CRUSTAL STRUCTURES OF SOUTH-EASTERN SICILY FROM REPROCESSING OF SEISMIC REFLECTION DATA IN THE FRAME OF THE SIRIPRO PROJECT

2009

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…

Sicily’s fold–thrust belt and slab roll-back: the SI.RI.PRO. seismic crustal transect

2016

Sicily is a thick orogenic wedge formed by (1) the foreland (African) and its Sicilian orogen and (2) the thick-skinned, Calabrian–Peloritani wedge. The crust under central Sicily, from the Tyrrhenian margin to the coastline of the Sicily Channel, has been investigated by the multidisciplinary (SI.RI.PRO.) research project. The project dealt with the nature and thickness of the crust and depth and geometry of the Moho, which is essential in formulating subduction models and improving the knowledge of African and Tyrrhenian–European lithospheres. The results resolve features such as (1) the main orogenic wedge, (2) the very steep, NW–SE-trending regional monocline suggesting inflection of th…

Role of extension and compression in the evolution of the eastem margin of Iberia: the ESCI- València Trough seismic profile

1994

Carlos.Santisteban@uv.es The ESCI-València Trough deep seismic reflection profile crosses the eastern margin of Iberia and can be divided into three regions according to crustal structure. From NW to SE they are: a) the Ebro Basin, whit a 33 km thick continental crust wich remained almost undeformed during the Cenozoic and is very reflective in its lower part; b) the Continental Margin, made up of the Catalan-Valencian Domain and the Balearic Promontory with a thin (12 to 30 km thick) continental crust wich was deformed during the Cenozoic, extensional structures predominating the first domain and contractional structures in the second; and c) the Algerian Basin, with a 9 km thick oceanic c…

Deep structural setting of the North American-Caribbean plate boundary in eastern Guatemala

2009

Se presenta un modelo bidimensional de gravedad para determinar la estructura en profundidad del sistema de fallas lateral-izquierda de Motagua-Polochic, que son parte del límite de las placas América del Norte y del Caribe. Estos elementos tectónicos, sismicamente activos, atraviesan oeste-este la región de Guatemala y se sobreponen a una línea de sutura donde afloran cuerpos ophiolíticos. En las principales zonas de desplazamiento de las fallas se han desarrollado cuencas de pull-apart y regiones de restricción (push-up). El análisis estructural de algunas de estas fallas, situadas a lo largo del valle Izabal y del valle Motagua, en combinación con los datos obtenidos del satélite, ha per…

Lithospheric P- and S-wave velocity models of the Sicilian area using WAM tomography: Procedure and assessments

2013

We present 3-D models of the P- and S-wave velocity distributions in the crust and uppermost mantle beneath Sicily, Calabria (Southern Italy), and surrounding submerged areas, obtained by tomographic inversion of traveltimes of regional body waves phases. Our method combines double-difference tomographic inversion with a post-processing procedure [Weighted Average Model method (WAM)]. This procedure was applied to a set of models consistent with the experimental data. We tested the ability of the WAM procedure to mitigate the uncertainty associated with the arbitrary nature of the many input parameters required for each inversion. The local reliability and resolution of the obtained models …