Okinawa - Part of the Pacific Rim of Fire

Early Saturday a powerful earthquake with a believed magnitude of 6.9 rattled Okinawa and the southern islands of the Ryukyu island chain, injuring two and initially prompting fears of a tsunami.

There were no reports of serious damage however. The quake is believed to be the strongest to hit Okinawa since 1909. The Okinawan people were understandably shaken. (Pardon the Pun) A Japanese news agencies reported that two people were hurt, but that there were no reports of any deaths. The only major damage reported hours after the quake was some ruptured water pipes in two locations, according to an Okinawan police official.

The quake was centered off the coast of Okinawa at a depth of 6.2 miles (10 kilometers) and occurred at 5:31 a.m. Saturday morning. (Okinawa Time)  A Meteorological Agency had initially predicted a tsunami up to 6 feet (2 meters) near the Okinawan coast and warned residents to stay away from the coastline but the agency lifted the warning within two hours after observing only a small swelling of the tide.

Here are a few comments I found from people who experienced the quake first hand.

"I was fast asleep when the quake hit, and I jumped out of bed. It felt like the shaking lasted forever," Ryota Ueno, a town official in the Nishihara district of Okinawa, told public broadcaster NHK.

Masaaki Nakasone, an official in Nanjo town, said his house shook violently but all furniture and other objects stayed intact. "First there was a vertical shaking, then the house swayed sideways."

Japan is one of the world's most earthquake-prone countries. As part of the Pacific Rim it has numerous Volcanoes and techtonic plates. See the graphic below. The diagram shows a remarkable fact about the surface of the Earth. Around the rim of the Pacific Ocean are many volcanoes. The rim of the Pacific Ocean also is the scene of much earthquake activity.

These volcanoes are most typically found in the regions where subduction is taking place.

The ring of volcanoes around the Pacific Ocean is called the "Pacific Rim of Fire".

The diagram shown here also shows (in yellow) the boundaries of many of the Earth's surface plates.

It is these plates shifting that cause many of the earthquakes Okinawa experiences. When these plates move it can also raise or drop the floor of the ocean causing tsunamis or huge ocean waves where the entire ocean raises and spreads outward from the center of the earthquake area.

While living in Okinawa, I remember several smaller earthquakes occurring. One of them waking my wife and I by moving the bed we were sleeping in across the smooth floor of our apartment bedroom. I remember waking up and not realizing what was happening at first but the it hit me and my idea of living on a cliff with a view of  the ocean immeadiately came into question. As it turned out there was no damage and we soon calmed down.

On another occassion there was a report of an off shore quake and a tsumami warning was issued. I remember the Far East Network TV station indicating that a tsunami would be arriving within the next 45 minutes. Being the naive 25 year old that I was at the time we rushed down to the Sunabe seawall to see this wave come into the shore. Duh! We were so stupid back then. Luckily though there really wasn't much of a wave hit the island, just a long continuous wave about four feet high with not much impact once it made the shoreline. Good thing or you may not have been able to read my blog today.

That's it for today see you all tomorrow! Stay Safe.