Quake Jolts Anchorage; No Damage
PALMER, Alaska (AP) _ A moderate earthquake hit Anchorage and its outskirts, but there were no reports of damage, officials at the Tsunami Warning Center of the National Weather Service reported.
The temblor registered 4.6 on the open-ended scale at just before midnight Thursday and was centered about 30 miles north of Anchorage, said Wayne Jorgensen of the quake observatory.
The Richter scale is a measure of ground motion as recorded on seismographs. Every increase of one number means a tenfold increase in magnitude. Thus, a reading of 7.5 reflects an earthquake 10 times stronger than one of 6.5.
An earthquake of 3.5 on the Richter scale can cause slight damage in a local area; 4 can cause moderate damage. An 8 reading is a ″great″ quake, capable of tremendous damage.
The 1964 Alaska quake that killed 131 people measured 8.4 on the Richter scale, while the San Francisco earthquake of 1906 has been estimated at 8.3.