Friday, October 2, 2009
Indonesia Living on the Edge, Geologically Speaking
Indonesia is the world’s fourth most-populous nation. It might also be considered the most watery: It consists of about 13,000 islands, some of which barely poke above the water line, some that disappear altogether at high tide.
The names of Indonesia’s major islands are as exotic as they are fabled — Java, Borneo, Sumatra, Papua, Bali. They are also some of the most rambunctious places on Earth, in terms of earthquakes, volcanoes and tsunamis. The tectonic plates beneath the islands are always heaving and grunting and sliding and sticking. Topside, the land spews and fumes and shudders and shrugs.
The two earthquakes that struck Sumatra this week were big underwater grunts, and they have killed hundreds of Indonesians, perhaps a thousand. Hospitals have collapsed. Hotels. A school. A mosque. And houses, so many houses.
Earthquakes are nothing new in Indonesia. In fact, they are to be expected: The nation sits astride the notorious Ring of Fire where 90 percent of the world’s earthquakes occur, usually the nastiest ones. But the hard facts of Indonesia’s geography do not soften the anguish of those who have lost fathers, mothers, sisters or friends, their homes and cars and pushcarts, their clothes and pets and wedding albums.
Sumatra, bisected by the equator, is certainly in the world’s hot zone. Its western coast is stippled with dozens of active volcanoes, three dozen or more. And just offshore lies the despicable Sunda Trench, part of the Ring of Fire. Toil and trouble, burn and bubble.
The Ring, which is more like a horseshoe, is that volatile network of volcanic arcs and oceanic trenches that nearly encircles the Pacific Ocean — from coastal Chile and Peru, up through Central America and Mexico, past California and under the chin of Alaska, left at Russia’s Far East, south through Japan, the Philippines, Indonesia and New Zealand.
The tectonic plates do not randomly drift or wander about the Earth's surfaceand are driven by definite yet unseen forces.