Reicherter et al. 2002b

Reicherter, K., Jabaloy, A., Galindo-Zaldívar, J., Becker-Heidmann, P., Reiss, S. (2002): Holocene palaeoseismic history of the Central Betic Cordilleras (S-Spain). – In: Leroy, S., Stewart, I. (Hg.): Environmental catastrophes and recovery in the Holocene (Volume of abstracts), S. 69–70. Atlas Conferences Inc.

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Abstract:

One of the most destructive earthquakes in Spain occurred in 1884 along the Ventas de Zafarraya Fault (VZF) located in the Central Betic Cordilleras. The normal VZF cuts the contact between the Alboran and the South Iberian Domains in the Betic Cordilleras. New palaeoseismic and radiocarbon data bracket the timing of pre-1884 ruptures along the fault during the last 10 ky, indicating earthquake recurrence intervals between 2 and 3 ky for major earthquakes of M > 6.5. The Holocene slip rate was estimated between 0.14 and 0.30 mm/a. The total slip of the fault is about 1500 m, the post-Tortonian mean slip rate is 0.2 mm/year.
Our palaeoseismic investigations are supplemented by high-resolution Ground-Penetrating Radar and by an assessment of the Recent and historical seismicity. The most important deformations and secondary features, like landslides and liquefaction, are related to the activity of the Ventas de Zafarraya Fault.
The VZF is exposed in a trench (36°57′ 500 N, 04°07’500 W) where three coarse grained wedges are intercalated with fine-grained relict palaeosols and wash-off sediments. The base of the lowermost wedge yields an age of 8800 ± 130 years BP. Approximately 8 km NE of the VZF 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 VZF 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 VZF and minor faults during the Holocene.

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