Accession Number : ADA031021


Title :   Long Period Seismic Waves


Descriptive Note : Final rept. 1 Jun 1972-31 Mar 1976


Corporate Author : SAN CALIXTO OBSERVATORY LA PAZ (BOLIVIA)


Personal Author(s) : Cabre, Ramon


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a031021.pdf


Report Date : Aug 1976


Pagination or Media Count : 37


Abstract : A High-Gain Long-Period seismic station (ZLP) was installed in a tunnel 90m long in the Zongo Vallye (16 deg 16 min 10.3 sec S, 68 deg 07 min 05. 3 sec, 4397m asl), where daily barographic changes do not exceed 3 mbars, to obtain high quality data both for Federal agencies research and for Observatorio San Calixto research. A microbarograph and standard meteorological instruments were added for convenient correlations. Also short-period seismographs, with a gain of one million for one second of period, were installed. The coefficients of the formula for calculation of seismic events local magnitude were found to be as it follows: M sub L = log (A/T) + + 1.51ogD + 2.0, for distances around 5 degrees. The study of internal structure of the earth has shown an improtant friction in the earthquakes occurring at the lithosphere bending. Models were developed and are presented for the seismic velocities as a function of depth beneath La Paz region, differing a little from one azimuth to another. A s contribution to seismicity studies, the main results of a particular earthquake are presented, together with a preliminary seismic risk map estimated according to enicenter locations and macroseismic data.


Descriptors :   *DISCRIMINATION , *EARTHQUAKES , *RISK ANALYSIS , *SEISMIC DETECTION , *SEISMIC WAVES , ATMOSPHERIC DISTURBANCES , BOLIVIA , EARTH CRUST , EXPLOSION EFFECTS , FRICTION , HIGH GAIN , INTENSITY , LITHOSPHERE , NOISE , RAYLEIGH WAVES , SEISMOGRAPHS , SEISMOLOGICAL STATIONS , SEISMOLOGY , TECTONICS , TIME , VELOCITY


Subject Categories : Seismology
      Seismic Detection and Detectors


Distribution Statement : APPROVED FOR PUBLIC RELEASE