About noon today, people in eastern Kentucky were startled by a novel event - an earthquake. The U.S. Geological Survey says a tremor shook the region near Whitesburg. It's a rural area about 150 miles southeast of Lexington, Ky., and about 140 miles northeast of Knoxville, Tenn. No one was hurt.
The magnitude was 4.3, which the USGS site says triggers a "sensation like a heavy truck striking the building" and is "felt by nearly everyone".
On April 11 of this year, an extraordinary cluster of earthquakes struck off Sumatra. The largest shock, magnitude 8.7, produced stronger ground-shaking than any earthquake ever recorded. And it surprised seismologists by triggering more than a dozen moderate earthquakes around the world.
The quakes are also a sign of big changes to come in the Earth's crust.
A powerful, 8.6-magnitude earthquake and an 8.2-magnitude aftershock off the west coast of Northern Sumatra today led authorities to warn that potentially devastating tsunamis might roar across the Indian Ocean.
But to the relief of millions who were immediately reminded of the devastating tsunami that rolled across that ocean in 2004, the waves generated by today's temblors were minor and the tsunami "watch" was canceled just before 9 a.m. ET.
The other welcome news: Initial reports indicated that damage from the quakes themselves may not have been extensive.
A huge earthquake shook the ocean floor off the coast of Indonesia Wednesday. Early measurements by the U.S. Geological Survey give it a strength of 8.7. Surrounding nations have issued tsunami warnings.