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UNIVERSIDAD DE CONCEPCION
INSTITUTO DE GEOLOGÍA ECONÓMICA APLICADA

Curso GEOLOGÍA y MINERALOGIA PARA INGENIEROS METALURGISTAS

Capítulo I-1 Interior de la Tierra y Conceptos básicos de Tectónica de Placas Parte 2
Relator : Dra. Ma. Eugenia Cisternas

Manifestaciones externas de la dinámica interna
• Los terremotos • Los volcanes • Las deformaciones: Pliegues y fallas

TerremotosLos terremotos aparecen asociados a los límites convergentes y transformantes. Sus consecuencias afectan a millones de personas que habitan zonas con algún tipo de riesgo sísmico.
• ¿Qué es un Terremoto? • ¿Por qué se produce? • ¿Cuál es la frecuencia de los terremotos? • ¿Cómo se registra un terremoto?

Ondas P: compresionales; velocidad: 6Km/seg; provocan cambios volumétricos; sepropagan en medios sólidos, líquidos, gaseosos

ONDAS P Y ONDAS S: Ondas de cuerpo

Ondas S: velocidad: 3,5 km/seg; no se propagan en medios líquidos; provocan cambios de forma http://www.umich.edu/~gs265/society/earthquakes.htm

http://www.umich.edu/~gs265/society/earthquakes.htm

ESCALA RICHTER Y Frecuencia
Magnitud Richter 8.0 Efectos cerca al epicentro Generalmente no es percibido, perosí registrado Potencialmente Perceptible Percibido por algunos Percibido por la mayoría Provoca daños Destructivo en regiones pobladas Terremoto mayor, genera daños cuantiosos Trremoto devastador, causa extensa destrucción cerca del epicentro Frecuencia por año 600,000 300,000 49,000 6200 800 266 18 1.4

ESCALA MERCALLI
I. Not felt except by a very few under especially favorable circumstances.II. Felt only by a few persons at rest, especially on upper floors of buildings. III. Felt quite noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. IV. During the day felt indoors by many, outdoors by few. Sensation like heavy truck strinking building. V. Felt by nearly everyone, many awakened. Disturbances of trees, poles and othertall objects sometimes noticed. VI. Felt by all; many frightened and run outdoors. Some heavy furniture moved; few instances of fallen plaster or damaged chimneys. Damage slight. VII. Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable in poorly built or badly designed structures. VIII. Damageslight in specially designed structures; considerable in ordinary substantial buildings with partial collapse; great in poorly built structures. (Fall of chimneys, factory stacks, columns, monuments, walls.) IX. Damage considerable in specially designed structures. Buildings shifted off foundations. Ground cracked conspicuously. X. Some well-built wooden structures destroyed. Most masonry and framestructures destroyed. Ground badly cracked. XI. Few, if any (masonry) structures remain standing. Bridges destroyed. Broad fissues in ground. XII. Damages total. Waves seen on ground surfaces. Objects thrown upward into air.

Magnitude 8.8 OFFSHORE MAULE, CHILE
Saturday, February 27, 2010 at 06:34:17 UTC

Although magnitude is still an important measure of the size of an earthquake,particularly for public consumption, seismic moment is a more physically meaningful measure of earthquake size. Seismic moment is proportional to the product of the slip on the fault and the area of the fault that slips. These “maps” of the slip on the fault surfaces of the January 12th M7.0 Haitian earthquake and the M8.8 Chilean earthquake show that, although the slip in Chile was only about 50% greater,the fault area was vastly larger. This accounts for the release of approximately 500 times more energy in the Chilean earthquake than in the Haiti earthquake.

Chile

Haiti

Finite fault models by Gavin Hayes, USGS National Earthquake Information Center

Chile 27 febrero 2010 (3.34 hrs)

Magnitude 8.8 OFFSHORE MAULE, CHILE
Saturday, February 27, 2010 at 06:34:17 UTC

El mapa de...