scholarly journals Fault zone properties affecting the rupture evolution of the 2009 (Mw6.1) L'Aquila earthquake (central Italy): Insights from seismic tomography

2011 ◽  
Vol 38 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
R. Di Stefano ◽  
C. Chiarabba ◽  
L. Chiaraluce ◽  
M. Cocco ◽  
P. De Gori ◽  
...  
Keyword(s):  
Fault Zone ◽  
Seismic Tomography ◽  
Central Italy ◽  
L’Aquila Earthquake

Outcrops and well logs as a practicum for calibrating the accuracy of traveltime tomograms

2015 ◽  
Vol 3 (3) ◽  
pp. SY27-SY40 ◽  
Author(s):  
Sherif M. Hanafy ◽  
Ann Mattson ◽  
Ronald L. Bruhn ◽  
Shengdong Liu ◽  
Gerard T. Schuster
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Great Basin ◽  
Seismic Tomography ◽  
Seismic Data ◽  
Hanging Wall ◽  
Normal Fault ◽  
Well Logs ◽  
Drill Core ◽  
Sufficient Detail

We have developed two case studies demonstrating the use of high-resolution seismic tomography and reflection imaging in the field of paleoseismology. The first study, of the Washington fault in southern Utah, USA, evaluated the subsurface deposits in the hanging wall of the normal fault. The second study, of the Mercur fault in the eastern Great Basin of Utah, USA, helped to establish borehole locations for sampling subsurface colluvial deposits buried deeper than those previously trenched along the fault zone. We evaluated the seismic data interpretations by comparison with data obtained by trenching and logging deposits across the Washington fault, and by drill-core sampling and video logging of boreholes penetrating imaged deposits along the Mercur fault. The seismic tomograms provided critical information on colluvial wedges and faults but lacked sufficient detail to resolve individual paleoearthquakes.

Shallow structural setting of an active normal fault zone in the 30 October 2016 Mw 6.5 central Italy earthquake imaged through a multidisciplinary geophysical approach.

2020 ◽  
Author(s):  
Fabio Villani ◽  
Stefano Maraio ◽  
Pier Paolo Bruno ◽  
Lisa Serri ◽  
Vincenzo Sapia ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Fault Zone ◽  
Central Italy ◽  
Normal Fault ◽  
Alluvial Fan ◽  
Fault System ◽  
Depth Range ◽  
Inversion Algorithm ◽  
Data Set ◽  
Refraction Tomography

<p>We investigate the shallow structure of an active normal fault-zone that ruptured the surface during the 30 October 2016 Mw 6.5 Norcia earthquake (central Italy) using a multidisciplinary geophysical approach. The survey site is located in the Castelluccio basin, an intramontane Quaternary depression in the hangingwall of the SW-dipping Vettore-Bove fault system. The Norcia earthquake caused widespread surface faulting affecting also the Castelluccio basin, where the rupture trace follows the 2 km-long Valle delle Fonti fault (VF), displaying a ~3 m-high fault scarp due to cumulative surface slip of Holocene paleo-earthquakes. We explored the subsurface of the VF fault along a 2-D transect orthogonal to the coseismic rupture on recent alluvial fan deposits, combining very high-resolution seismic refraction tomography, multichannel analysis of surface waves (MASW), reflection seismology and electrical resistivity tomography (ERT).</p><p>We acquired the ERT profile using an array of 64 steel electrodes, 2 m-spaced. Apparent resistivity data were then modeled via a linearized inversion algorithm with smoothness constraints to recover the subsurface resistivity distribution. The seismic data were recorded by  a190 m-long single array centered on the surface rupture, using 96 vertical geophones 2 m-spaced and a 5 kg hammer source.</p><p>Input data for refraction tomography are ~9000 handpicked first arrival travel-times, inverted through a fully non-linear multi-scale algorithm based on a finite-difference Eikonal solver. The data for MASW were extracted from common receiver configurations with 24 geophones; the dispersion curves were inverted to generate several S-wave 1-D profiles, subsequently interpolated to generate a pseudo-2D Vs section. For reflection data, after a pre-processing flow, the picking of the maximum of semblance on CMP super-gathers was used to define a velocity model (VNMO) for CMP ensemble stack; the final stack velocity macro-model (VNMO) from the CMP processing was smoothed and used for post-stack depth conversion. We further processed Vp, Vs and resistivity models through the K-means algorithm, which performs a cluster analysis for the bivariate data set to individuate relationships between the two sets of variables. The result is an integrated model with a finite number of homogeneous clusters.</p><p>In the depth converted reflection section, the subsurface of the VF fault displays abrupt reflection truncations in the 5-60 m depth range suggesting a cumulative fault throw of ~30 m. Furthermore, another normal fault appears in the in the footwall. The reflection image points out alternating high-amplitude reflections that we interpret as a stack of alluvial sandy-gravels layers that thickens in the hangingwall of the VF fault. Resistivity, Vp and Vs models provide hints on the physical properties of the active fault zone, appearing as a moderately conductive (< 150 Ωm) elongated body with relatively high-Vp (~1500 m/s) and low-Vs (< 500 m/s). The Vp/Vs ratio > 3 and the Poisson’s coefficient > 0.4 in the fault zone suggest this is a granular nearly-saturated medium, probably related to the increase of permeability due to fracturing and shearing. The results from the K-means cluster analysis also identify a homogeneous cluster in correspondence of the saturated fault zone.</p>

3D Digital Outcrop Model analysis of fracture networks: insights from the Mt. Vettore Fault Zone.

2021 ◽  
Author(s):  
Riccardo Inama ◽  
Yuri Panara ◽  
Niccolò Menegoni ◽  
Filippo Carboni ◽  
Giovanni Toscani ◽  
...  
Keyword(s):  
Fault Zone ◽  
Central Italy ◽  
Structural Evolution ◽  
Fracture Network ◽  
Geometrical Parameters ◽  
Fracture Density ◽  
Coseismic Slip ◽  
Major Fault ◽  
Mapping Techniques ◽  
Digital Outcrop

<p>In the last years, several studies investigated the Mt. Vettore Fault Zone (MVFZ), activated during the 2016 Central Italy seismic sequence. Research has focused mainly on aftershocks and mainshock locations, coseismic slip and surface cracks, while an accurate study of the fracture network in the MVFZ was never conducted.</p><p>In this study we present a fracture analysis performed using very high resolution (0.5 – 5 cm) Digital Outcrop Models (DOMs) that developed by Unmanned Aerial Vehicle (UAV)-based digital photogrammetry. The UAV gave the possibility to investigate outcrops with dimensions up to hundreds of metres high and wide, and acquire big and precise fracture data using 3D digital automatic and manual mapping techniques. To investigate the structural variability of the MVFZ fracture network, we realized several DOMs located in different positions, along and around the major fault. All the selected outcrops are formed by Calcare Massiccio Fm., which better records brittle deformation in the study area.</p><p>This analysis aimed to better understand the MVFZ fracture network, including mechanics, kinematics and local structural evolution. In particular, it allowed to determine: 1) the main sets of fractures; 2) the geometrical parameters of the fracture network (e.g. fracture density, persistence, roughness and aperture); 3) the relative timing of the main tectonic brittle events. The preliminary analysis of the DOMs suggests a variability of the fracture network parameters over the MVFZ, especially for what concerned fracture set orientation and density. </p><p> </p><p> </p>

Impact of the 6 April 2009 L'Aquila earthquake on groundwater flow in the Gran Sasso carbonate aquifer, Central Italy

2010 ◽  
Vol 25 (11) ◽  
pp. 1754-1764 ◽  
Author(s):  
Antonella Amoruso ◽  
Luca Crescentini ◽  
Marco Petitta ◽  
Sergio Rusi ◽  
Marco Tallini
Keyword(s):  
Groundwater Flow ◽  
Central Italy ◽  
L’Aquila Earthquake ◽  
Carbonate Aquifer ◽  
2009 L’Aquila Earthquake

scholarly journals Coseismic ground deformation of the 6 April 2009 L'Aquila earthquake (central Italy, Mw6.3)

2010 ◽  
Vol 37 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
P. Boncio ◽  
A. Pizzi ◽  
F. Brozzetti ◽  
G. Pomposo ◽  
G. Lavecchia ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Central Italy ◽  
L’Aquila Earthquake ◽  
2009 L’Aquila Earthquake
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