Magma intrusion as a driving mechanism for the seismic clustering following the 9 May 1989 earthquake swarms at the Canary Islands

Abstract

A b s t r a c t On 9 May 1989 a M L = 5.2 earthquake struck a region between the islands of Tenerife and Gran Canaria. We investigated the time-spatial evolution of seismic patterns affecting the Canary Islands region during 1989-1995, using a quantitative spatial fractal analysis method. This method allows quantitative investigation of subtle trends in seismicity distribution through time. The fractal analysis indicates that epicenters clustered around a large zone during the May 1989 sequence affected narrow zones during 1991-1993, but then larger zones during 1993-1995 with an overall trend to shallower focal depths. The spatial localisation of seismic data and its time evolution appear to be related to magmatic rather than tectonic activity. Spatial clustering properties of seismicity are consistent with a major intrusive episode in 1989, followed by a period of quiescence and renewed deep intrusive activity from 1993 onwards. This interpretation suggests an increasing probability of future volcanic hazard in the region investigated.

Aeromagnetic anomalies reveal the link between magmatism and tectonics during the early formation of the Canary Islands

“…They interpreted the seismotectonic origin for this earthquake as a sinistral strike-slip fault located between Tenerife and Gran Canaria with a reverse component of motion resulting in the underthrusting of the western block (Tenerife) and a southwest relative displacement of Tenerife with respect to Gran Canaria and Africa. Other authors, however, proposed a volcanic origin for this earthquake 55 .…”

Methodology for geohazard assessment for hydropower projects

“…(Biggs et al, 2013) IS (Eggert and Walter 2009;Zobin 2001;Vinciguerra and Day 2013;Biggs et al 2013;Martens and White 2013) IW from GF into Res. Disruption of generation facilities.…”