328 TECTONICS/Earthquakes Figure 14 Destruction of the housing development at Turnagain Point above the Bootlegger Clay, Anchorage, 1994 The bluff moved 606 m towards the bay, and 75 homes were destroyed Sand lenses in the clay lost strength (photograph National Geophysical Data Center, USA) set in motion, fatally burying 36 people at a camp site In Peru in 1970, rock and ice slides triggered by an earthquake killed 20 000 people Disease The risk of disease is a major concern after earthquakes, particularly in hot climates Water supplies may be cut off and the populace may resort to using polluted supplies of water mixed with sewage and drainage effluents, which may be contaminated by corpses Starvation Normal food supplies may be cut off and transport arteries may be blocked, so it is important to bring in food supplies immediately from the world outside Exposure The 1988 Spitak earthquake in Armenia illustrates the problem of exposure Many people lost their dwellings and were living in the open in very cold December climatic conditions The need for tents, warm clothing, and blankets was urgent Looting Looting is prevalent after earthquakes Mitigation The potential for mitigation of the earthquake hazard is limited The main ways of mitigating the hazard are through good building and constructional design, planning development away from at-risk areas, and warning However, warning is a very difficult matter Research into earthquakes is at an interim stage, and the scientific community is at present by no means in consensus about the physical processes involved There is the problem of how threatened populations react to warnings: if the event fails to occur, especially more than once, the population may not heed future warnings; alternatively, giving a warning to evacuate may engender panic In countries with controlled political systems, such as China, warning and evacuation may be easier than in a democratic Western country The Chinese did evacuate the city of Haicheng twice in 1974 and 1975, on December and again on February, based on seismology, community monitoring levels, radon gas in water, water temperature, tiltmeters, magnetometer readings, and patterns of animal behaviour An earthquake of magnitude 7.3 struck at 7.36 am on February However, the great Tangshan earthquake of 1976 struck without any prediction or warning and killed at least 240 000 people (possibly many more) Millions of US dollars have been spent on research into earthquakes in California, and some improvement in prediction has been achieved, yet the existence of the Northridge Fault, the site of the 1994 earthquake, which killed 60 people and caused 20 billion dollars worth of damage, was not even known before the event The best mitigation procedure would be to have international teams ready with emergency supplies and equipment, trained personnel, and sniffer dogs, at a distance from earthquake-prone regions, ready to been flown in by plane and helicopter Research into earthquakes The most important research into earthquakes has involved statistical,