Presentation on theme: "Tectonic Hazards A PowerPoint of images to accompany the notesheet."— Presentation transcript:
Tectonic Hazards A PowerPoint of images to accompany the notesheet
EARTHQUAKES Mexico City 1985 Ground shaking PRIMARY HAZARD Long Waves Nature of surface (dried up lake bed)
Loma Prieta epicenter PRIMARY (San Francisco 1989) Marina District badly affected Foundations on rubble infill after 1906 earthquake. Lessons not learnt so repetition of disaster. SECONDARY fire
Leninakan Armenia PRIMARY HAZARD On December 7, 1988, a magnitude 6.9 earthquake shook northwestern Armenia Collapse of floors leaving walls standing in building in Leninakan. This three-story building is one of the older buildings. Most of the newer one-and two- story dwellings and two- and three-story commercial buildings in Leninakan received little damage deaths.
When liquefaction occurs, the strength of the soil decreases and, the ability of a soil deposit to support foundations for buildings and bridges is reduced – see the overturned apartment complex buildings in Niigata in SECONDARY HAZARD
LANDSLIDES Earthquakes can dislodge glacier chunks causing disastrous mudflows.
Tsunami e.g. Banda Ache Asian Tsunmai December 26 th 2004 SECONDARY HAZARD
VOLCANOES Basalt lava flow Kilauea, Hawaii Predictable and not too hazardous PRIMARY HAZARD
Death by pyroclastic flow can be terrifyingly brutal. In less than a second, the body is submerged in fire... the first breath vaporizes the internal organs... the pain barely has a chance to register... the body is almost instantly reduced to charcoal Pyroclastic flow is composed mainly of volcanic rock and dense ash material and is ejected from an exploding volcano. Up to 200 kph. PRIMARY HAZARD
ASH FALL PRIMARY HAZARD
The Great Farting Lake of 1986 – Lake Nyos Cameroon VOLCANIC GASES On August 21, 1986 is erupted in quite an unexpected manner. The lake itself basically turned over, allowing trapped gas to diffuse all at once, creating an enormous pool of CO2 that killed more than 1700 people and their livestock. PRIMARY HAZARD
Lahars – SECONDARY HAZARDS In the aftermath of Pinatubo, Phillipines – every year in heavy rains more lahars occur. The eruption was 1991.
Lahar – Nevada del ruiz – worst volcanic disaster of 20th Century
Mt. St Helens LANDSLIDE triggered eruption SECONDARY HAZARD
Destruction at the village of Teles, located at the outer edge of the area inundated by the tsunami. In many areas, bare house poles and debris where all that remained of homes. A total of 10,000 survivors lost their homes and personal possessions. TSUNAMI 1999 New Guinea SECONDARY HAZARD