|
|||||
|
|
Energy partitioning during seismic slip in pseudotachylyte-bearing faults (Gole Larghe Fault, Adamello, Italy) |
|
| Authors: | Lidia Pittarello Giulio Di Toro Andrea Bizzarri Giorgio Pennacchioni Jafar Hadizadeh Massimo Cocco |
| Institution: | aDipartimento di Geoscienze, Università di Padova, via Giotto, 1, 35137-Padova, Italy bIstituto di Geoscienze e Georisorse, Unità operativa di Padova, CNR, via Giotto, 1, 35137-Padova, Italy cIstituto Nazionale di Geofisica Vulcanologia, Sezione di Bologna, via Donato Creti, 12, 40128–Bologna, Italy dIstituto Nazionale di Geofisica Vulcanologia, Sezione di Roma, via di Vigna Murata, 605, 00143-Roma, Italy eDepartment of Geography & Geosciences, University of Louisville, Louisville, Kentucky 40292, USA |
| Abstract: | The determination of the earthquake energy budget remains a challenging issue for Earth scientists, as understanding the partitioning of energy is a key towards the understanding the physics of earthquakes. Here we estimate the partition of the mechanical work density into heat and surface energy (energy required to create new fracture surface) during seismic slip on a location along a fault. Earthquake energy partitioning is determined from field and microstructural analyses of a fault segment decorated by pseudotachylyte (solidified friction-induced melt produced during seismic slip) exhumed from a depth of ~ 10 km—typical for earthquake hypocenters in the continental crust. Frictional heat per unit fault area estimated from the thickness of pseudotachylytes is ~ 27 MJ m− 2. Surface energy, estimated from microcrack density inside clast (i.e., cracked grains) entrapped in the pseudotachylyte and in the fault wall rock, ranges between 0.10 and 0.85 MJ m− 2. Our estimates for the studied fault segment suggest that ~ 97–99% of the energy was dissipated as heat during seismic slip. We conclude that at 10 km depth, less than 3% of the total mechanical work density is adsorbed as surface energy on the fault plane during earthquake rupture. |
| Keywords: | earthquakes pseudotachylyte particle size distribution energy partitioning surface energy frictional heat |
| 本文献已被 ScienceDirect 等数据库收录！ | |