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Estimación de la dimensión fractal de la actividad sísmica intermedia en el Noroeste Argentino

2007; National University of Tucumán; Volume: 20; Issue: 1 Linguagem: Inglês

1852-6217

Lidia Beatriz Esper, Marta E. Torres, Graciela González Júarez,

Complex Systems and Time Series Analysis

espanolSe presenta el calculo de la dimension fractal de la actividad sismica intermedia, es decir, la producida entre 70-300 km de profundidad en la region N.O.A., donde la actividad sismica dominante es una consecuencia directa de la subduccion de la placa de Nazca bajo la placa Sudamericana. Para identificar la propiedad fractal en el area bajo estudio, se utilizo el metodo de distribucion de tamanos (magnitudes). Se trabajo con la base de datos del USGS “Nacional Earthquake Information Center” y el analisis se realizo con el software IASPEI “Algorithms for Earthquake Statistic & Prediction” – International Association of Seismology and Physics of the Earth´s Interior (USA). Se estimo la dimension fractal (D) para sismos de magnitudes medianas (de 4 a 6 en la escala de Richter) y grandes magnitudes (mayor que 6 en la misma escala) considerando el periodo entre 1933-2001, y se obtuvieron: D1 = 1,11902 ± 0,00086 y D2 = 0,80789 ± 0,01979 respectivamente. El analisis realizado en esta region indica que la relacion entre la dimension fractal y el exponente de escala de la ley exponencial de Gutenberg-Richter depende de la magnitud de los sismos. EnglishEstimation of the fractal dimension of intermediate seismic activity in Northwestern Argentine Region”. The aim of this paper is to estimate the fractal dimension of seismic activity at the depth between 70-300 km (intermediate) in the northwestern argentine region; where the prevailing activity is a direct consequence of the subduction of the Nazca Plate under the South American Plate. In order to identify fractal property in the area under study, the method of size distribution was used. This investigation was carried out with the database obtained from the USGS National Earthquake Information Center and the analysis was conducted with the IASPEI (Algorithms for Earthquake Statistics & Prediction) software. Fractal dimension (D) was calculated for earthquakes of medium magnitude (4-6 on the Richter scale) and high magnitude (higher than 6 on the same scale), during a period between 1933-2001, and D1 = 1,11902 ± 0,00086 and D2 = 0,80789 ± 0,01979 being obtained respectively. The analysis effected in this region indicates that the D and b ratio depends on earthquake.