December 2015 – BOISE, Idaho — More than 40 small earthquakes were recorded in east-central Idaho last week in what experts say is another earthquake swarm in the region. Officials in the Challis area on Friday reported no damage from the micro-quakes that started Tuesday and have mostly gone unnoticed or unreported in an area with residents accustomed to more vigorous shaking. But the temblors ranging up to 2.9 magnitude have perked up scientists trying to understand the fault system in the area where a 5.0 magnitude quake struck in January. Challis is about 170 miles from Yellowstone.
“Such earthquake swarms typically are associated with the movement of molten rock below ground,” which geologists credited for the recent quake cluster at Yellowstone National Park, “or they may be linked to an active fault,” said Bill Phillips, a geologist with the Idaho Geological Survey at the University of Idaho.
“What has many of us scratching our heads is the present-day swarm doesn’t appear to be on the big, active fault in the area that ruptured in 1983 and caused the largest earthquake in Idaho,” Phillips said.
Scientists brought in temporary seismometers last year during a previous earthquake swarm and then earlier this year put in a permanent seismometer near Challis. The swarms are occurring within the Centennial Tectonic Belt extending west from Yellowstone National Park. The park is well known as a geologic hotspot, but scientists said that doesn’t explain the swarms in east-central Idaho. –Trib, MSB
Quake shakes Western Greece: A tremor measuring 4.4 Richter rattled parts of western Greece on Saturday, the Athens-based Geodynamic Institute reported. The earthquake, which occurred shortly after 10.30 a.m., was felt in Achaia and Ilia, in the Peloponnese, on the Ionian island of Zakynthos and in parts of Aetoloacarnia, in western central Greece. The quake’s epicenter was located near Kyllini, in the Peloponnese. –Ekathimerini