"Alaska Earthquake Center"

The earthquake centered in Lake Clark National Park shook Southcentral Alaska Tuesday at about 1:40 p.m.

A magnitude 2.5 earthquake struck Carroll Inlet, about 15 miles northeast of Ketchikan.

The Alaska Earthquake Center said the quake was an aftershock of the magnitude 8.2 earthquake that reverberated in communities along the Alaska Peninsula in July — the country’s largest in half a century.

The magnitude 8.2 earthquake that struck off Alaska’s southwest coast Wednesday night gave nearby residents a good shake and triggered tsunami warnings, but there were no large waves or any immediate reports of major damage or injuries.

The quake has triggered a tsunami warning for a swath of coastal Alaska from Sand Point to Kodiak to Homer to Cordova, and prompted sirens to sound in communities as evacuations began.

Ice quakes are believed to occur around Mt. Ogden east of Juneau when water gets underneath Wright Glacier, causing it to slip. They also occur when a glacier calves, a crevasse opens up or icebergs scrape against each other.

The Alaska Earthquake Center puts the epicenter directly under the Riggs Glacier in the park. The area is accessible to permitted boaters, backcountry campers and charter operators.

The seismic stations are part of the U.S. Array, a multi-million dollar national research project. It spanned nearly two decades and the entire continent.

When all that rock fell, it shook the earth equivalent to a magnitude 2.8 or 2.9 earthquake.

The earthquake’s epicenter was around 15 miles deep and occurred on the Queen Charlotte Fault.