Washington, July 29 : A massive earthquake measuring 8.2 on the Richter scale jolted Alaska and prompted authorities to issue tsunami warnings for parts of the state, according to the US Geological Survey. The temblor occurred at around 10.15 p.m. on Wednesday night and was located 91 km east southeast of Perryville, said the USGS. It added that at 46.7 km, the earthquake is considered shallow and there have been at least two strong aftershocks, including a preliminary magnitude 6.2 and magnitude 5.6. According to the US National Tsunami Warning Center, a tsunami warning has been issued for South Alaska and the Alaska Peninsula, from Hinchinbrook Entrance to Unimak Pass; and for the Aleutian Islands, from Unimak Pass, to Samalga Pass. Meanwhile, a tsunami warning has also been issued for Hawaii, said the National Weather Service Pacific Tsunami Warning Center. /IANS