Parts of Alaska are under tsunami advisories after an 8.2 magnitude earthquake struck off the state's coast, according to preliminary data from the US Geological Survey. The very strong quake was located about 56 miles (91 kilometers) east southeast of Perryville, Alaska & occurred around 10:15 pm on July 28 night local time, USGS said. At 29 miles deep (46.7 km), the earthquake is considered shallow. Shallow earthquakes are between 0 and 70 km in depth. There have been at least two strong aftershocks, including a preliminary magnitude 6.2 and magnitude 5.6, the USGS reports. A tsunami warning had been issued for portions of the state shortly after the quake, according to the US National Tsunami Warning Center, which said in an update, "A tsunami has been confirmed and some impacts are expected.” Watch the video to know more.