Reicherter et al. 2002a

Reicherter, K., Jabaloy, A., Galindo-Zaldívar, J., Becker-Heidmann, P., Reiss, S. (2002): Holocene paleoseismic history of the Ventas de Zafarraya Fault (S-Spain). Erlanger Geologische Abhandlungen (Sonderband 3 (TSK 9)): 77.

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Abstract:

One of the most destructive earthquakes in Spain occurred in 25th December 1884. Coseismic deformations and surface ruptures were reported along the Ventas de Zafarraya Fault located in the Central Betic Cordilleras during this event. The normal Ventas de Zafarraya Fault has a mean ESE-WSW strike and dips around 60º towards the North, it cuts the contact between the Alborán and the South Iberian Domains in the Betic Cordilleras.
The Ventas de Zafarraya Fault is exposed in a trench (36°57’ 500 N, 04°07’500 W) where three coarse grained wedges are intercalated with fine-grained relict paleosols and wash-off sediments. The base of the lowermost wedge yields a 14C age of 8.800 ± 130 years BP. Approximately 8 km NE of the Ventas de Zafarraya Fault, in Llanos de la Dona, a minor fault scarp is developed (N 37° 01´ 401, W 4° 03´ 490). A trench across the scarp exhibited three tapering colluvial wedge deposits. These are herewith interpreted for the first time as “rockfall wedges“, generated by seismic shaking. In contrast to the Ventas de Zafarraya Fault scarp, where we dated the actual faulting events, the duration of seismic quiescence, i.e. the soil formation intervals, has been dated. In conclusion, three major earthquakes M ≥ 6.5 have been detected along the studied segment of the Ventas de Zafarraya Fault and minor faults during the Holocene. These data bracket the timing of pre-1884 ruptures along the fault during the last 10.000 y, indicating earthquake recurrence intervals between 2.000 and 3.000 y for major earthquakes of M ≥ 6.5. The Holocene slip rate was estimated between 0.14 and 0.30 mm/year. The total slip of the fault is about 1500 m, and the post-Tortonian mean slip rate is 0.2 mm/year.
High-resolution Ground-Penetrating Radar supplements our paleoseismic investigations. The most important deformations and secondary features, like landslides and liquefaction, are related to the activity of the Ventas de Zafarraya Fault.

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