Volcanic haze advisory for NI cancelled

The Emergency Management Office cancelled yesterday morning the volcanic haze advisory for Agrihan, Pagan, and Alamagan after information from the National Weather Service in Tiyan, Guam, showed the volcanic haze from Anatahan moving away from the Northern Islands.

The information was received at about 6:40am yesterday morning.

EMO said that animated satellite imagery and surface observations indicate that the narrow volcanic plume of dust from Anatahan volcano is shifting toward the northwest.

Typhoon Haitang continues to move westward away from the Marianas, allowing winds below 15,000 feet back toward the southeast. This will carry the haze and ash from Anatahan into the Philippine sea away from the Northern Marianas.

EMO said that the plume from the Anatahan volcano is moving north-northwestward away from Agrihan, Pagan, and Alamagan. Winds from the southeast were expected to continue yesterday and last night.

This comes even as tremor and ash emission levels on Anatahan have intensified, with the erupting volcano recently throwing out an ash plume to 36,000 feet in the air.

On Thursday, the volcano kicked up ash to 10,000 feet, the U.S. Geological Survey and the EMO said.

“Pilot reports have located ash west of Rota and northwest of Tinian at 10,000 feet,” they added.

The Air Force Weather Agency’s satellite monitoring of the extent of the ash plume was obscured by Typhoon Haitang near Agrigan.

In a joint report, the USGS and EMO said small long-period earthquakes have been occurring on Anatahan every two to three minutes. The agencies said tremor levels increased from 60-80 percent of the peak levels observed on June 17-26.

On June 19, a 2.6-minute eruptive pulse sent ash to 50,000 feet, matching the intensity of Anatahan’s strongest historical eruption last April 6, which also sent ash to 50,000 feet for about an hour.

“Over the past 27 hours, three ash events were detected that may have exceeded 30,000 feet,” the agencies said. “Additional ash pulses are likely as long-period activity continues.”

They said the volcano spewed out ash to 36,000 feet at about 9am Wednesday; 30,000 feet, 2:44pm; and 31,000 feet, 5pm.

The agencies said they have yet to restore Anatahan’s seismic stations that have malfunctioned due to heavy ashfall. Last Sunday, they said signals were restored from one of the seismic stations on Anatahan and another one on Sarigan.

The agencies said the volcano remains in a state of continuous eruption. They advised aircraft to pass upwind of the island or beyond 10 nautical miles downwind, pointing out that conditions could change rapidly, and volcanic activity could suddenly escalate.