By means of linear regression, an empirical expression was derived to estimate the height of the F region peak (hmF2) which, among other 7 measures calculated, offers the best adjustment with the N(h) profiles data obtained in Havana. Statistical analysis…

An automatic data acquisition system for field resistivity measurements was developed at CICESE. The system applies a known current to the ground, measures the induced voltage, and calculates the apparent resistivity. All measurements are converted to digital format, at a…

Gravimetric data have been accumulated on 22 calderas mainly in Japan. For some, explosion-seismic data or drilling results are also available. Synthesizing these data, some common features of their subsurface structure are deduced. Although all Japanese calderas are relatively young,…

Detailed paleomagnetic, rock-magnetic, ore-microscopy, scanning electron microscopy (SEM) and anisotropy of magnetic susceptibility (AMS) studies of volcanic units from Arandas-Atotonilco, NW Jalisco State, Mexico are reported. Units are basaltic and basaltic-andesites flows of Miocene age (date by K-Ar). The magnetic…

Based on the volumes of the erupted material and duration times of the March-April 1982 eruptions of the El Chichón volcano, the heights and flow velocities of the eruptive columns are evaluated. The velocities obtained are higher than 400 m/sec…

Even after proper field static corrections are applied, the lack of continuity in the reflection horizons in a seismic section can be attributed to residual static effects produced by lateral heterogeneities, topographic irregularities and/or changes in the velocity of the…

Levels of oxidants in the atmosphere at several sites in the Mexico City Metropolitan Area have been recorded since 1975. Evidence of atmospheric transport of pollutants such as ozone have been observed towards the southern end of the Mexico Valley…

Data from µ-meson telescopes, at different underground depths, have been compared with the predictions of a solar-controlled mechanism proposed by Swinson. The observations at ground level and at moderate depths show a significant field-polarity dependent effect of the kind envisaged…

Uranium, Thorium and Potassium contents of some igneous and sedimentary rocks of the Guanajuato Mineral District have been measured by γ-ray scintillation spectrometry. Preliminary measurements show that the area studied is not a province of high radioactive contents. The data…

A method is presented for the estimation of seismic risk in regions whose seismic history is incomplete and for which no acceleration data exists, based on Monte Carlo Simulations of the seismic process, using a minimum of assumptions.Application of this…