Publication Date:
2021-01-07
Description:
Detailed studies of earthquakes triggered by a known source of stress change can shed light on the influence of fault frictional properties and preseismic stress on the initiation, propagation and arrest of seismic ruptures. Triggered and induced seismicity can provide unique opportunities to understand this problem. However, direct evidence is rare due to the absence of e.g., near-field surface ground deformation observations and unknown pre-earthquake stress conditions. Here, we collect geodetic data recording the coseismic effects of the Mw 5.1, 11 May 2011 Lorca (SE Spain) moderate earthquake. Elastic modelling results suggest that the nucleation process and main slip area occurred at very shallow depths (2-4 km) on the rupture plane along the Alhama de Murcia fault. Slip extends towards the surface from unstable to stable friction fault segments. We find that the slip area matches well a pattern of positive Coulomb stress change due to groundwater extraction in a nearby basin aquifer. These results indicate that the shallow slip distribution during the earthquake could be controlled by groundwater induced unloading stresses at the upper frictional transition of the seismogenic layer. The relationship between known crustal stress changes (e.g., groundwater extraction) and coseismic slip distribution could help, in general, to understand where and how earthquakes tend to occur.
Description:
Our research was funded by an Ontario Early Researcher Award, the CSRN NSERC Strategic Network Grant, and the NSERC and Aon Benfield/ICLR IRC in Earthquake Hazard Assessment. Additional support was provided by the MICINN (Ministerio de Ciencia e Innovación) projects CGL2005-05500-C02, CGL2008-06426-C01-01/BTE, PCI2006-A7-0660, and AYA2010-17448; as well the Moncloa Campus of Excellence (UCM-UPM, CSIC). Radar data were obtained by the ESA (European Space Agency)-CAT1:4460 and 6745 projects.
Description:
Published
Description:
821-825
Description:
3.2. Tettonica attiva
Description:
JCR Journal
Description:
restricted
Keywords:
2011 Lorca earthquake
;
InSar and GPS
;
Modelling
;
groundwater crustal unloading
;
04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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