Abstract

Analysis of seismicity can illuminate active fault zone structures but also deformation within large volumes of the seismogenic zone. For the Mw 6.5 2016–2017 Central Italy seismic sequence, seismicity not only localizes along the major structures hosting the mainshocks (on-fault seismicity), but also occurs within volumes of Triassic Evaporites, TE, composed of alternated anhydrites and dolostones. These volumes of distributed microseismicity show a different frequency-magnitude distribution than on-fault seismicity. We interpret that, during the sequence, shear strain-rate increase, and fluid overpressure promoted widespread ductile deformation within TE that light-up with distributed microseismicity. This interpretation is supported by field and laboratory observations showing that TE background ductile deformation is complex and dominated by distributed failure and folding of the anhydrites associated with boudinage hydro-fracturing and faulting of dolostones. Our results indicate that ductile crustal deformation can cause distributed microseismicity, which obeys to different scaling laws than on-fault seismicity occurring on structures characterized by elasto-frictional stick-slip behaviour.

A new study sheds light on earthquake physics, showing that lithological and rheological heterogeneities in the rocks composing the seismogenic layer strongly influence seismicity distributions and earthquake scaling laws.

Details

Title
Rock and fault rheology explain differences between on fault and distributed seismicity
Author
Collettini, C. 1   VIAFID ORCID Logo  ; Barchi, M. R. 2   VIAFID ORCID Logo  ; De Paola, N. 3   VIAFID ORCID Logo  ; Trippetta, F. 4   VIAFID ORCID Logo  ; Tinti, E. 5   VIAFID ORCID Logo 

 Università di Roma La Sapienza, Dipartimento di Scienze della Terra, Rome, Italy (GRID:grid.7841.a); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy (GRID:grid.410348.a) (ISNI:0000 0001 2300 5064); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Firenze, Italy (GRID:grid.182470.8) 
 Dipartimento di Fisica e Geologia Università degli Studi di Perugia, Perugia, Italy (GRID:grid.9027.c) (ISNI:0000 0004 1757 3630) 
 Durham University, Department of Earth Sciences, Durham, UK (GRID:grid.8250.f) (ISNI:0000 0000 8700 0572) 
 Università di Roma La Sapienza, Dipartimento di Scienze della Terra, Rome, Italy (GRID:grid.7841.a); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Firenze, Italy (GRID:grid.182470.8) 
 Università di Roma La Sapienza, Dipartimento di Scienze della Terra, Rome, Italy (GRID:grid.7841.a); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy (GRID:grid.410348.a) (ISNI:0000 0001 2300 5064) 
Publication year
2022
Publication date
2022
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2718022495
Copyright
© The Author(s) 2022. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.