A 7.0-magnitude earthquake hit Japan's Kumamoto region on Friday, the day after a 6.2 quake struck, killing at least nine people, according to the U.S. Geological Survey. Friday's quake struck at a depth of about 6 miles around 9:25 a.m. PST, around 1:30 a.m. Saturday local time. Tsunami advisories have been issued for parts of the Asian island nation, the Japan Meteorological Agency told CNN. A tsunami was not expected for California, Oregon, Washington, Alaska or British Columbia, the National Weather Service tweeted. The temblor occurred about 7 miles from Thursday's 6.2-magnitude earthquake, which struck southwestern Japan's Kyushu island, killing nine people. Thursday's quake was a foreshock, according to Dr. Lucy Jones, formerly of USGS. Only 5 to 10 percent of earthquakes are foreshocks worldwide, and about 30 to 50 percent are preceded by foreshocks, she tweeted. A 7.0-magnitude earthquake is considered more than 6 times bigger than a 6.2 on a seismogram, but feels nearly 16