5.1 earthquake off coast of Japan and 6.2 in Papua, New Guinea

An earthquake rocked the Japanese cities of Honshu and Narita today. No tsunami alert has been issued so far, and no injuries are reported.

The Honshu area has been the location of frequent earthquake activity in recent months. USGS reports the quake located near the east coast of Honshu was one of the strongest to hit the region this month.

The quake was five miles west of Sawara, six miles northeast of Narita and six miles west of Katori-shi. It was felt at least eight miles away southeast of INashiki, according to the United States Geological Survey (USGS).

Ring of Fire

Papua, New Guinea also suffered a quake of 6.2 magnitude Sunday. The USGS reported the quake was 64 miles southeast of Angoram, 73 miles northeast of Mt. Hagen. No reports of injuries have been reported.

Both Japan and New Guinea are part of what is called the Ring of Fire in the Pacific encompassing 25,000 miles. This is an area where a significant number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. It is a horseshoe shaped configuaration containing oceanic trenches, volcanic arcs, and volcanic belts responsible for tectonic plate movement. 452 volcanoes are located around this ring called the circum-Pacific belt or circum-Pacific seismic belt.

About 90 percent of the world’s earthquakes occur along the Ring of Fire.

The Ring of Fire is defined by what is called plate tectonics, which is the movement and collisions of the plates as they shift beneath the ocean. The Pacific plate is being subducted, which is the sinking of one crustal plate under another as they collide. This is taking place along the Kamchatka Peninsua arcs on the south past Japan. The southern portion includes a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga and New Zealand and Australia. The Alpide belt along the west of Sumatra, Java, includes the site of the recent quake in New Guinea.

Resources

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc000c3e9.php#details

http://news.lalate.com/2012/08/20/japan-earthquake-today-2012-strikes-near-narita-honshu/

http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire