Deformación cortical de las Béticas Orientales observada mediante GPS y su relación con el terremoto de Lorca

Abstract

ResumenEl 11 de Mayo del 2011 tuvo lugar una serie sísmica en la localidad murciana de Lorca. El terremoto principal de M w 5.2 se atribuye a la Falla de Alhama de Murcia, una de las fallas más activas del SE de la Península Ibérica. Mediante el análisis de las cinco campañas GPS de la red CuaTeNeo realizadas entre 1997 y 2011 se ha caracterizado el campo inter-sísmico de velocidades de la zona. Las velocidades de las estaciones más cercanas a la Falla Alhama de Murcia detectan el carácter inverso y de desgarre de esta falla. Las estaciones situadas entre la costa Mediterránea y la falla presentan las máximas velocidades de la zona (entre 1.4 y 1.8 mm/a) con una orientación NNO, oblicuas a la traza de esta. La cinemática de la falla deducida a través de las tasas deformación obtenidas a partir de los vectores GPS de la red CuaTeNeo coincide con el mecanismo focal obtenido para el terremoto. El análisis en detalle de la estación GPS continua en Lorca permite la detección de un salto co-sísmico de ~6 mm hacia el Norte. Palabras clave: deformación cortical, GPS, Béticas, terremoto de Lorca. GPS crustal deformation of the Eastern Betics and its relationship with the Lorca earthquake AbstractOn May 11 th of 2011, a seismic series occurred near the city of Lorca (Murcia). The main earthquake of magnitude M w 5.2 has been attributed to the Alhama de Murcia Fault, one of the most active faults in the SE Iberian Peninsula. We analyzed data from 5 GPS campaigns of the CuaTeNeo network conducted between 1997 and 2011. The velocities of the stations closest to the Alhama de Murcia Fault show the reverse and strike-slip direction of motion. Stations located on the southeastern side of the fault have the maximum velocities in the area (between 1.4 and 1.8 mm/yr), oriented towards NNW direction, obliquely to the trace of the fault. The kinematics of the fault and the strain rate directions obtained from the CuaTeNeo network GPS measurements matches the calculated focal mechanism of Lorca earthquake. Detailed analysis of the time-series from the continuous GPS station at the Lorca city allows the detection of co-seismic offset of ~6 mm to the North.

Crustal deformation in eastern Betics from CuaTeNeo GPS network

“…The absence of co-seismic signal in the CuaTeNeo data is expected, since the elastic dislocation model for the event predicts no co-seismic displacement for any of its stations Frontera et al, 2012). However, a continuous station placed in Lorca, did detect a co-seismic jump of ~4-6 mm to the north as predicted by the modeling (Echeverria et al, 2012;Frontera et al, 2012).…”

“…This paper does not address vertical deformation rates since the analyzed campaign style GPS velocities do not provide sufficient resolution to detect possible deformations of a few mm/yr. It is noteworthy to mention that previous InSAR and GPS studies of the Guadalentín sedimentary basin where the city of Lorca is located (Figures 1 and 2) has experienced subsidence of up to 1 meter in the last ten years (at a rate of ~100 mm/yr) related to groundwater extraction (Echeverria et al, 2012;Frontera et al, 2012;González and Fernández, 2011;González et al, 2012). This rate of subsidence is two orders of magnitude higher than the expected tectonic signal and is more than sufficient to be detected by the campaign observations.…”

IoT-Based Geotechnical Monitoring of Unstable Slopes for Landslide Early Warning in the Darjeeling Himalayas

“…These thresholds can be used to determine the temporal probability of the occurrence of landslides as a part of a landslide early warning system (LEWS). The thresholds can be estimated using empirical methods [9][10][11][12], probabilistic methods [8,13,14], and/or physical methods [15,16], and we can use other tools like geographic information system (GIS) [17] and global positioning system (GPS) [18,19] and new technologies in order to make the calculation processes automatic [20,21]. When long-term monitoring data is not available for the study area, it is often difficult to identify the triggering rainfall corresponding to landslides [22].…”

Campo de deformación cortical actual de la Península Ibérica estimado a partir de medidas GPS

“…However, in the more recent history, since the seismic instruments were put in place, no significant (EMS > 7.0) crustal type earthquakes have been recorded in the area. The most recent damaging earthquake that occurred in Spain, was the M w 5.1 2011 Lorca earthquake (Echeverria et al, 2012;Pro et al, 2014), that occurred in SE Betics as result of a slip on Alhama de Murcia fault. As can be seen from Figure 2, seismicity is mainly concentrated in the southern part of the Peninsula, in the Betic-Rif arc and the Pyrenees.…”