UNDRO 91/1291
CHILE - VOLCANIC ERUPTION/EARTH TREMORS
INFORMATION REPORT NO. 1
19 AUGUST 1991
SITUATION
1. HUDSON VOLCANO IN SOUTHERN CHILE (45.54' S, 72.58' W) HAS ERUPTED WITH GREAT VIOLENCE SINCE 13 AUGUST 1991 CAUSING VERY THICK ASHFALL DOWNWARD (EAST) OF VOLCANO WITH REPORTED ACCUMULATION OF 250 CM CLOSE TO VOLCANO, 65 CM AT 35 KM DISTANCE, 15 CM AT 130 KM, 8 CM AT 180 KM.
2. THE VOLCANO IS 2,500 M HIGHT WITH A LARGE GRACIER OF ABOUT 60 SQUARE KM AND ICE VOLUME AT LEAST 2.5 CUBIC KM. SO FAR ONLY SMALL SCALE MELTING HAS OCCURED BUT MORE WIDESPREADED MELTING PRODUCE MAJOR MUDFLOWS THREATENING SEVERAL THOUSAND PEOPLE LIVING DOWN MAIN RIVER DRAINAGES.
3. PRELIMINARY INDICATIONS ARE THAT ASH IS UNUSUALLY RICH IN FLUORIDES WITH THREAT OF WATER AND PASTURE CONTAMINATION.
RESPONSE
4 . AUTHORITIES HAVE EVACUATED 235 PEOPLE LIVING IN RIVER VALLEYS WITHIN 50 KM OF VOLCANO, AND ARE READY TO EVACUATE ABOUT 1,000 MORE AT GREATER DISTANCE (FORTUNATELY, HUMAN POPULATION IS VERY SPARSE AROUND THE VOLCANO).
5. GOVERNMENT HAS REQUESTED INTERNATIONAL ASSISTANCE WITH MONITORING AND RISK ASSESSMENT AND UNDRO/UNDP ARE IN PROCESS OF ARRANGING LOAN OF RADIO-LINKED SEISMOGRAPHS AND TECHNICAL ASSISTANCE FROM COLOMBIA AND EQUIPMENT/EXPERTISE FROM USA FOR FIELD MEASUREMENT OF FLUORIDES AND OTHER POSSIBLE TOXIC SUBSTANCE.
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DPR 310 CHL'91(1)