Thursday, March 31, 2011

6.4 Fiji quake sends more warning signs for Pacific Ring of Fire

March 31, 2011 – WAILAGI LALA, FIJI (BNO NEWS) — A strong earthquake struck the South Pacific Ocean on early Thursday afternoon, not far from an island part of Fiji, seismologists said. No tsunami warnings were issued. The 6.4-magnitude earthquake at 12.11 p.m. local time (0011 GMT) was centered about 130 kilometers (80 miles) east of Wailagi Lala, the northernmost outpost of Fiji’s Lau Islands with no known population. It struck about 23.7 kilometers (14.7 miles) deep, making it a shallow earthquake, according to the United States Geological Survey (USGS). The USGS estimated that 2,000 to 3,000 people in the region may have noticed weak to light shaking, but said no damage was to be expected. “There is a low likelihood of casualties and damage,” the agency said. The Pacific Tsunami Warning Center did not issue a tsunami warning. –Channel 6 News

This is the 7th quake to strike Fiji in a week. This is more evidence that our preliminary assessment of volcanic and seismic activity along the volcanic trench of Tonga-Kermadec in the subduction zone has been in a period of escalation for the last 3 months. The Tonga Trench in the South Pacific Ocean is 10,882 meters (35,702 ft) deep at its deepest point which is known as the Horizon Deep. Under the sea, the Pacific Plate is being subducted below the Tonga and the Indo-Australian Plate. In this transform fault zone, where plates also slide in horizontal fashion, the convergence is taking place at a rate estimated at approximately 15 centimeters (6 inches) per year; however, recent Global Positioning Satellite measurements indicate in places a convergence of up to 24 centimeters (10 inches) per year is occurring across the northern Tonga Trench. This is the fastest plate velocity recorded on the planet. This results in the earth’s most active zone of mantle seismicity, where mantle is essentially devoured and recycled. This process takes place under both tremendous heat and pressures. The escalation of seismic activity in this region, Tonga, New Zealand, Kermadec may be one more indication also that geothermal gradient is increasing. The Fiji quake and resulting stress on the Pacific Plate was almost immediately followed by yet another 6.2 earthquake off the eastern coast of Japan. The Pacific Ring of Fire is becoming more volatile and dangerous and this seismic dynamism continues to perturb the stability of surrounding plates in the region

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