By BRYAN WALSH
Earthquakes have always been part of Los Angeles' past — and its future. In 1994 a 6.7-magnitude quake hit the Northridge area of the city, badly damaging freeways, killing more than 70 people and causing $20 billion in damages. But those numbers could be dwarfed by a major quake in the future. The geologic record indicates that huge quakes occur roughly every 150 years in the region — Los Angeles lies along the southern end of the San Andreas Fault — and the last big quake, which registered a magnitude 7.9, happened in 1857. Los Angeles has done a lot to beef up its building codes and emergency response in the 15 years since the Northridge quake and may be better prepared than any other major American city, but the city's sheer size ensures the next Big One will be bloody.Tokyo
By BRYAN WALSH
Roughly the same size as California, Japan shares the Golden State's precarious plate tectonics. The nation's four main islands get hit regularly with earthquakes of varying strength. But while California has about 36 million people, Japan's population is nearly 4.5 times as large, and most Japanese live in extraordinarily dense cities. That puts more people squarely in a danger zone — nowhere more so than in the capital of Tokyo, which has a population of 13 million. A major quake struck the city and its surroundings in 1923, killing as many as 150,000 people. Although Japan has vastly improved its infrastructure since then and has the strictest building codes in the world, a similar temblor — which seismologists believe is almost inevitable — could kill more than 10,000 people and cause more than $1 trillion in damages. Tehran
By BRYAN WALSH
All of Iran lies within a major earthquake zone, and the country has suffered terrible temblors before — most recently in 2003, when a 6.8-magnitude quake leveled the ancient city of Bam and killed more than 30,000 people. But a similar quake in the congested capital of Tehran — where more than 7 million people live — would be a shattering catastrophe. Unlike building codes in other endangered cities such as San Francisco and Tokyo, Tehran's are relatively lax, and many residents like in the sort of unreinforced-concrete houses that turn into death traps in the event of a strong quake. The Iranian Health Ministry once estimated that a 7-magnitude quake would destroy 90% of the city's hospitals. Tehran is so threatened that there has been periodic talk about moving the capital. Pacific Northwest
By BRYAN WALSH
The rain-drenched residents of the Cascadia region — roughly from Oregon to southern British Columbia — probably assume that earthquakes are something for their neighbors in California to worry about. But Cascadia sits on top of major faults, and although it doesn't get hit very often, the region has been seen massive quakes before. The most recent one was in 1700, when a megathrust earthquake that may have been as severe as 9.2 on the Richter scale struck the region. The geological record indicates that a catastrophic quake hits Cascadia only about every 500 years, but the cities of the Pacific Northwest, like Seattle and Vancouver, are far less prepared than San Francisco and Los Angeles for a major earthquake, so when the next powerful temblor comes around, the Pac Northwest could suffer. Indonesia
By BRYAN WALSH
It's called the Ring of Fire, a semicircle of violently shifting plates and volcanoes that runs along the edges of the Pacific Ocean, from New Zealand to Chile. The most seismically active region on the planet, the Ring of Fire has triggered countless quakes, volcanic eruptions and tsunamis, including the 2004 Indian Ocean tsunami that killed 230,000 people, mostly in Southeast Asia. That tsunami was set off by a 9.3-magnitude quake near the northern coast of Sumatra, Indonesia, a region that has been hit repeatedly by massive temblors, most recently a 7.6 earthquake in September that killed more than 1,000 people. Sadly that's a relatively small quake death toll by Indonesian standards — and seismologists expect more to come in the future. source: Time.com