No abstract

The Jalisco region of western Mexico is the locus of interaction among the North America, Cocos, and Rivera plates, giving rise to the Jalisco block. This region is one of the most tectonically active in Mexico, and here took place the largest instrumentally recorded earthquake in Mexico the twentieth century, on 3 June 1932 (M 8.2), three important tsunamis in the last 100 yrs, and two of the most active volcanoes in Mexico. Nevertheless, the first seismicity studies here, undertaken with temporary networks, did not commence until 1994. In 2008, the Government of Jalisco and the University of Guadalajara funded a research project to install a seismic network in this region. The principal objective was to study the seismic hazard in the region and characterize seismic parameters in the different areas to design building codes. The Red Sísmica y Acelerométrica Telemétrica de Jalisco (RESAJ) project was thus initiated in 2009. Its Central Lab is at Centro de Sismología y Volcanología de Occidente (SisVOc), located at the Universidad de Guadalajara in Puerto Vallarta. Currently, the RESAJ has 26 telemetered and 2 autonomous stations. The RESAJ serves as the seismological lab for the postgraduate program at SisVOc.

No abstract

A model of the seismic source of the October 9, 1995 Jalisco-Colima tsunami is obtained using the numerical modeling of the tsunami by considering an earthquake (Mw~8.0) with rupture area A = 9000 km 2 , L = 150 km, W = 60 km, with two different coseismic dislocation km along the fault plane starting from its NW edge, offshore Chalacatepec and Chamela, and 3 m the dislocation of the next 90 km; offshore Tenacatita, Navidad and Manzanillo. As expected, the seismic source obtained in of the seismic source obtained by inverting seismic and GPS data. However, the fact that the location of the rupture area and its coseismic dislocation is still important in order to provide some degree of certainty for the tsunami source of those historical tsunamis for which no seismic nor tide records are available, and only testimonies and vague relates of its effects are documented.

Ocean hydrothermal activity is well known from deep-sea studies; however, few studies have been reported at shallow depth. A shallow submarine hydrothermal system at Punta Mita described in 2000 was studied to determine the grain size classification of the marine sediments of this hydrothermal system. Three sites with hydrothermal activity were included. Each one was divided into three areas: with hydrothermal activity, intermediate, and out of hydrothermal activity. In each area, two sediment cores were randomly collected by scuba diving (number of sediment cores = 18). All sediment samples were subjected to a previous treatment, to eliminate salts and organic matter. The grain sizes were sieved and then classified following the Udden–Wentworth scale. A principal coordinate analysis was performed to determine if there was any association of the statistical moments with the areas and sites of study. The textural composition of the sediments in the hydrothermal influence areas is sand, where the very fine sand is the dominant grain size, which was confirmed with the mean moment. The sediments are characteristic of the tidal areas, except for those sediments in the areas with hydrothermal activity.