Plate Tectonics

Major Earthquake Due to Hit Southern California, Study Says

Publication: National Geographic News   Date: June 21, 2006   View Article

Get ready for the Big One.

About 300 years of pent-up stress in southern California is sufficient to trigger a catastrophic earthquake on the San Andreas Fault system, according to a new study.

Deep Sea Volcano Erupts on Film – A First

Publication: National Geographic News   Date: May 24, 2006   View Article

Billowing ash plumes, molten sulfur droplets, feisty shrimp feasting on fish killed by noxious gases, red lava jetting from a vent—they’re all part of the action recently filmed at an underwater volcano in the western Pacific Ocean.

The images are the first ever direct observations of an active, submarine arc volcano. These volcanoes grow near trenches that form where one piece of Earth’s oceanic crust slips beneath another.

100 Years Later, San Francisco Ripe for Another Megaquake

Publication: National Geographic News   Date: April 13, 2006   View Article

A hundred years ago a massive earthquake reduced much of the San Francisco Bay Area to piles of smoldering rubble.

As the anniversary of that disaster approaches, scientists are warning that the heavily populated California region has a 62 percent chance of a magnitude 6.7 or greater quake between now and 2032.

Why Was South Asia Hit Hard by Major Quake

Publication: National Geographic News   Date: October 13, 2005   View Article

The magnitude 7.6 earthquake that shook a broad swath of South Asia on October 8 resulted from the same forces that give rise to the world’s tallest mountains, the Himalaya, experts say.

The Earth’s crust is broken up into a jigsaw puzzle of plates constantly on the move. Some collide, others drift apart. They all jostle along in fits and starts like uncomfortable strangers in a packed crowd.

Sumatra Poised for Another Tsunami, Study Says

Publication: National Geographic News   Date: June 8, 2005   View Article

The earthquake- and tsunami-battered region of Sumatra, Indonesia, is at risk for more temblors and killer waves, seismologists cautioned today in a new study.

Study co-author John McCloskey, a seismologist at the University of Ulster in Northern Ireland, said the finding adds urgency to the push for greater earthquake and tsunami preparedness in the Indian Ocean region.

Tsunami Region Ripe for Another Big Quake, Study Says

Publication: National Geographic News   Date: March 16, 2005   View Article

The earthquake that triggered the December 26 tsunami has increased stress on nearby faults, making another major South Asian quake more likely, scientists reported today.

The magnitude 9 earthquake was centered off the west coast of Sumatra, an Indonesian island. The quake shifted nearly 97,000 square miles (250,000 square kilometers) of terrain along the Sunda trench subduction zone, where the Indonesian and Australian tectonic plates dive beneath the Burma tectonic plate.

Tsunami-Battered Sumatra Ripe for More Disasters

Publication: National Geographic News   Date: January 7, 2005   View Article

The force of the magnitude 9 earthquake that struck northern Sumatra on December 26, 2004, may have caught much of the world by surprise. But scientists say the region has a violent geologic past and is ripe for more cataclysmic earthquakes and volcanic eruptions in the millennia to come.

The Indonesian island sits in an area of the Indian Ocean where several large chunks of Earth’s crust, known as tectonic plates, collide. Tectonic plates can slip past, beneath, and over the top of each other. In the Sumatra region, the Indian and Australian plates are slowly creeping alongside and—in a process called subduction—diving beneath, the Burma plate, part of the larger Eurasian plate.

© 2008-2010 Collected Writings By John Roach