 |
| Titel |
Hydraulically-induced earthquake swarms: Geological evidence from the Adamello Batholith in the Southern Italian Alps. |
| VerfasserIn |
Eddie Dempsey, Bob Holdsworth, Giulio DiToro, Andrea Bistacchi |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075419
|
|
|
|
|
|
| Zusammenfassung |
| Earthquake swarms are often characterised by clusters of seismic events with highly variable earthquake focal mechanisms, irrespective of whether or not they are associated with a main shock event. Our current understanding of how such events manifest themselves in the geological record is based largely on the Hill (1977) and Sibson (1996) ‘fracture mesh’ models. Whilst these simple models are theoretically sound for homogeneous isotropic rock masses, they do not account for the effects of variably oriented pre-existing mechanical anisotropies and how these may lead to a more complex fracture evolution and geologic strain.
Interconnected networks of faults and veins filled with zeolites and other hydrothermal minerals are widespread in many orogenic terrains, including deformed granitic plutons and regions of metamorphic basement. Typically the fracture fills formed late in the tectonic history, at relatively low temperatures (e.g. < 200°) and depths (< 7 km), and appear to represent a late phase of fluid flow and mineralisation developed during the final stages of exhumation.
Here we focus on zeolite-bearing mineralised fractures associated with the Gole Larghe Fault Zone in the Southern Italian Alps. These mineralized veins, faults and fracture meshes are consistently found associated with variably orientated pre-existing structures and display strong evidence of elevated pore-fluid pressures. They initially formed as tensile/hybrid fractures and, once local rock cohesion was lost, accommodated small magnitude (
|
|
|
|
|
|
|