Thursday, July 07, 2005
Anatahan's volcano spits out ashes
Early Sunday afternoon, the U.S. Geological Survey and the Emergency Management Office reported that seismicity on Anatahan had significantly dropped, a possible indication that the continuing eruption might be waning. Later in the afternoon, small explosions and long-period earthquakes began to occur.At about 4:46pm Sunday, the volcano experienced a six-minute eruptive pulse that sent ash to 40,000 feet. Upper level ash clouds moved south-southeast and eventually dissipated.
"However, despite the ash dissipating, volcanic smog reached Tinian and Saipan and a commercial pilot reported volcanic smog at 20,000-30,000 feet," the agencies said.Anatahan continued to experience small explosions and long-period earthquakes with magnitudes of 1.5 to 2, which occurred at brief intervals of one to a few minutes apart.At 4:30am yesterday, the EMO issued another advisory informing the public that the governor had cancelled the volcanic haze alert for Saipan and Tinian.
But Babauta reminded all mariners to avoid passing near Anatahan due to continuous volcanic activity.The EMO and the USGS advised aircraft to take extra precaution within 10 nautical miles of island. The agencies said aircraft should pass upwind of the island or beyond 10 nautical miles downwind, pointing out that conditions could change rapidly and that volcanic activity could suddenly escalate.In joint report yesterday, the EMO and the USGS said a "moderately dense" cloud of ash and steam rose to 20,000 feet and moved northwest.
The ash plume extended about 80 nautical miles northwest of the island."Beyond that, residual thin ash and volcanic smog from last week's continuous eruption extend 360 nautical miles to the west of the island, and a second area of residual thin ash and volcanic smog 30 nautical miles wide and 200 nautical miles long extend northward," the agencies said.Over a week ago, the agencies disclosed that seismic equipment on Anatahan might have been damaged due to the unusually heavy ash emissions from the volcano.
They said repairs would be attempted as soon as eruptions drop sufficiently and wind directions change.On June 19, the volcano displayed a series of strong eruptions, which sent ash to 50,000 feet. That activity matched the intensity of Anatahan's strongest historical eruption last April 6, which also sent ash to 50,000 feet. The April 6 eruption spewed out approximately 50 million cubic meters of ash.