Popocatepetl Volcano - Update 008

The following reports were received by the Global Volcanism Network via email on the afternoon of 5 March 1996. Data are preliminary and subject to change. Additional information will be provided when available if this eruption continues.

At 03:49:30 on March 5 (All times local = GMT - 6), an ash emission event was detected at Popocatepetl Volcano. A continuous seismic signal of variable amplitude started abruptly at that time. This tremor remained at relatively high levels for about one hour, and then decreased, keeping an almost constant amplitude, which remains to the time of this report (1400, March 5).

Mild ashfalls have been reported in the immediate area around the volcano, particularly in the North sector. During a helicopter reconnaissance flight, at 1200, ash deposits were confirmed, especially in the close neigborhood of Tlamacas, and covering the snow cap. An ash and gas column about 800 m high rising vertically could be seen, height at which it dispered in a long plume towards the NorthEast. A sulfur smell could clearly be perceived near the crater. The emission of gas, steam and ash appeared to be generated from the same three sources in the eastern internal side of the crater that produced the 1994-1995 activity. In general terms, this event seems very similar to that of December 21, 1994, but perhaps about an order of magnitude lower, and comparable to the levels of activity observed on December 26, 1994. The only activity that may be regarded as precursory, is a small A-type event at 02:27:40 (M = 1.16). At this stage no changes in the level of alert have been issued, but monitoring is kept at the maximum level.

Information Contacts: Servando De la Cruz-R, Roberto Quaas W, Enrique Guevara, Bertha Lopez, Alicia Martinez, Carlos Gutierrez, CENAPRED, Mexico.

After several months during which only fumarolic gases were being emitted at Popocatepetl it is now certain that emissions of ash resumed this morning. I just returned from a helicopter reconnaissance flight around Popo. The glacier and snow are entirely covered by ash, confirming statements made by direct witnesses who saw ash emissions this morning. From vents located at the base of the eastern inner crater walls a vigorous column of steam could be seen at 12.00 P.M from the helicopter. Seismograms indicate that the renewed emission of ash might have started this morning at 3.50 AM.

Information Contact: Claus Siebe, Instituto de Geofisica, UNAM.