Publication: Velocidad de desplazamiento de la falla de Alhama de Murcia calculada mediante técnicas paleosismológicas y morfotectónicas
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Publication Date
2016
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Sociedad Geológica de España.
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Abstract
Se calcula la velocidad de desplazamiento de la falla de Alhama de Murcia mediante la aplicación de dos técnicas: a) la paleosismología y b) el análisis morfotectónico. Estas metodologías basan el cálculo en la velocidad en la dislocación tectónica de un elemento lineal de edad conocida. Se han excavado trincheras 3D en el segmento Lorca-Totana con el fin de identificar y medir la dislocación de un paleocanal enterrado. La edad del canal ha sido delimitada gracias a dataciones de OSL, radiocarbono y series del uranio aplicadas a pequeñas cantidades de carbonato pedogénico. La velocidad total obtenida es 0.9 mm/a. En la terminación sur de la falla (segmento Goñar-Lorca) se han analizado ocho canales dislocados en superficie. Las edades máximas de estos canales (edad de la superficie en la que se encajan) se han aproximado gracias a dataciones publicadas basadas en la termoluminiscencia, junto con nuevas dataciones de carbonato pedogénico. La velocidad lateral mínima obtenida con esta metodología es de 1.7-1.6 mm/a. Estos valores, coincidentes con los de las trincheras 3D y mayores a los obtenidos hasta la fecha, reafirman la falla de Alhama de Murcia como una de las más activas de la Zona de Cizalla de las Béticas Orientales.
We calculated the slip rate of the Alhama de Murcia fault by means of two techniques: a) paleoseismology, and b) a morphotectonic analysis. These methodologies measure the offset of a linear feature whose age is known. In the Lorca-Totana segment of the fault, we carried out a three-dimensional trenching campaign to identify and measure the offset of a buried paleochannel. The age of the paleochannel was constrained by new approaches of OSL, radiocarbon and U-series applied to small amounts of pedogenic carbonate datings. The mean net slip rate obtained is 0.9 mm/a. In the southernmost termination of the fault (Goñar-Lorca segment), we analysed eight offset channels in surface. The maximum ages of the channels (age of the surface in which they are entrenched) were estimated in base of previous geomorphological maps and of published ages (thermoluminescence) together with new datings of pedogenic carbonate. The minimum lateral slip rate for the fault in this area is 1.7-1.6 mm/a. These slip rate values position the Alhama de Murcia fault as one of the most active faults in the Eastern Betics Shear Zone.
We calculated the slip rate of the Alhama de Murcia fault by means of two techniques: a) paleoseismology, and b) a morphotectonic analysis. These methodologies measure the offset of a linear feature whose age is known. In the Lorca-Totana segment of the fault, we carried out a three-dimensional trenching campaign to identify and measure the offset of a buried paleochannel. The age of the paleochannel was constrained by new approaches of OSL, radiocarbon and U-series applied to small amounts of pedogenic carbonate datings. The mean net slip rate obtained is 0.9 mm/a. In the southernmost termination of the fault (Goñar-Lorca segment), we analysed eight offset channels in surface. The maximum ages of the channels (age of the surface in which they are entrenched) were estimated in base of previous geomorphological maps and of published ages (thermoluminescence) together with new datings of pedogenic carbonate. The minimum lateral slip rate for the fault in this area is 1.7-1.6 mm/a. These slip rate values position the Alhama de Murcia fault as one of the most active faults in the Eastern Betics Shear Zone.