natural disasters in the cordillera blanca, peru

Natural disasters in the Cordillera Blanca, Peru

• Major tectonic faults that are active

• Marked glacierization

• Geologically young, steep mountains

• Pro-glacial lakes

• Immediate vicinity of human settlements

ALPAMAYO

HU

AN

DO

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ARTESONRAJU

Mt HUASCARAN, PERU

1962 HUASCARAN AVY

• Large snow year

• 50 degree F increase in temp over a few minutes

• Caused avalanche

• 4,000 fatalities

• Yungay protected by ridge

1970 Avalanche

• Triggered by 7.7 magnitude earthquake

• Rock face failure

• Incorporated 30 meters of snow and ice!

• Moraines confined flow initially

• Accelerated over a distance of 2.4 km

• Became airborne at change of slope

Church before 1970 avalanche. Note palm trees in foreground.

Many years after the avalanche. Note palm trees survived.

Yungay is now completely abandoned. Cemetery has a monument to the dead.

Guiness book of records as the most deaths ever from an avalanche

A potential disaster in the icy Andes: a regrettable blunder

May 3, 2003: “NASA feels the heat as glacier pictures cause unrest in Peru”, according to Nature

HUARAZ CASE STUDIES

• On April 2, 2003 a NASA press release (http://photojournal.jpl.nasa.gov/catalog/PIA03899) gave reason to a major concern in Peru by stating the following: "A chunk of glacier was threatening to fall into an Andean lake and cause major flooding in a Peruvian city of 60,000. A fissure has appeared in the glacier that feeds Lake Palcacocha near the city of Huaraz, 270 km north of Lima. If the piece breaks off, ensuing floods would take 15 minutes to reach the city." The statement was based on the evaluation of an ASTER/TERRA (Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA's Terra satellite) image taken on November 5, 2001. A second press release was made on April 11, 2003, adding to the previous a most recent ASTER/TERRA image taken on April 8, 2003.

1941 Huaraz Disaster

• Moraine damming the proglacial Lake Palca (cocha = lake: Palcacocha) broke

• Resulting flood killed 6,000 people in Huaraz

HUARAZ, circa 1970

1970 Earthquake that caused the Huascaran disaster killed about 40,000 people in Huaraz.

Streets of Huaraz after the1970 Earthquake.

Adobe houses collapsed, killing people inside.

ASTER image,2001

Fissure

NASA interprets as huge crevasse

ASTER image,2003

Fissure

NASA believes glacial release into the lake is imminent

Palcacocha

Rock band from glacial retreat, not crevasse.

LAGO PARON

Located above Yungay

Potential Pro-glacier flood

1940’s flood from glacier failure

Huge rock glacier dammed lake.Could collapse at any time.

Summary

• 1962 Huascaran avalanche killed 4,000• 1970 Huascaran avalanche killed 20,000• 1941 proglacial lake outburst from

Palcacocha killed 6,000 in Huaraz• Lago Paron could have an outburst at any

time from (a) collapse of rock glacier damn; (b) glacial ice fall into lake; c) combination of both