Objective
Northern Venezuela is within the interaction zone between the Caribbean and South American tectonic plates. This plate boundary displays a wide zone of deformation where tectonic activity is accompanied by moderate to high seismicity and with several destructive earthquakes within historical record. Two microseismicity studies, in northwest and northeast Venezuela respectively, were performed to evaluate seismology parameters and to improve the knowledge of the present-day tectonic regime of these regions. The seismicity distributions for the two areas involved in the study are quite different. The instrumental record for the western area contains only 101 events most of them being shallow. The eastern area is much more active with at least thirteen destructive earthquakes documented within the historical record since 1530.
The microseismicity studies were carried out using 60 portable seismological stations deployed in both surveyed areas. Each site was selected according to criteria such as spacing, background noise, known seismicity and the presence of possible seismogenic structures. In general terms, the spacing between stations varied from 10 to 15 kilometres covering an area of about 287000 square kilometres in the west and 26000 squarekilometres in the east. The actual time during which the complete set of stations was operational was 14 weeks for the western array and 13 weeks for the eastern array. Data processing for the western network has just started. An average of 10 events per day could be correlated. The most seismically active area is around Churuguara which is responsible for about 50% of the events correlated. The peninsula and the western part of the array seem to be less active. The processing for the eastern network has also been started. Here the number of events per day is higher than that of the western network. Seismic activity appears to be concentrated at the north-eastern part of the network near the villages of El Pilar and Casany. Da ta processing will take a further few months with the first reliable results expected to be available by the end of 1991.
Topic(s)
Data not availableCall for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
20146 HAMBURG
Germany