Valena Berry and Rachel

Valena Berry and Rachel KenneyValena Berry and Rachel Kenney

Southern Chilean Andres, South America

6.21 miles NE of the town of Chaitén on the Gulf of Corcovado

Elliptical Caldera: 1.55 x 2.49 miles wide

Summit Elevation: 3,681 Ft.

Last eruption: 9,400 yrs ago.

Ash plume rose over 13.05 miles in altitude and drifted SSE.

Lightning storm with eruption. Dubbed a ‘Dirty Thunderstorm’.

Ashfall continued to occur daily in large plumes through to the 6th of May.

May 2nd: Government declared state of emergency and evacuated several hundred people from the town of Chaitén 6.21 miles SE of the volcano.

May 3rd through the 6th: reported 4,000 to 5,000 people evacuated from Chaitén and surrounding area.

May 5th: evacuation of Futaleufú, 40.4 miles ESE, took place. ~11.81 inches of ash had accumulated. One elderly person died during the evacuation.

A new lava dorm growth on the large one within the caldera.

24th of May, observation of a vigorous explosion from the old dome and the new dome overtakes it in height.

Ash plumes continue to rise, but only 1.86 to 3.11 miles in height.

Early in the month, ash and steam plumes rose to 4.35 miles in altitude.

6,200 acres of forest to the N and NE sides burned by pyroclastic flows and lateral explosions.

Ash plumes remain at 1.86 miles in altitude.

Lahars overtake drainages during June 27th and 28th, especially in the Chaitén and Amarrillo rivers.

Agriculture Impacts

Main concerns: Lahars and Tephra Farm Land Area Affected:Effects: Good and Bad

Livestock

Death: Livestock buried in pasturesSkin Fungal infectionsAccelerated wear on teeth and gumsGovernment provided farm-recovery funds

Structural DamageUrban and Rural Communities:Individual town: Futeleufú 300mm ash (11.81 inches)Disrupted water, electricity, transportation, and telecommunication.Residential/commercial damage:GuttersRoof cladding corrosionStructural roof damageInternal ash contaminationHydro-electric damsBridges destroyed by lahars

AviationMass flight cancellationsClosed airports Ash in airspace weeks afterTurbine damage

Volcanic Lightning Storm: How do they form? A “shear layer” of intense horizontal winds and “updraught” from the volcano

create multiple vortices that counter-rotate. Eddies form inside, because of instability Expanding umbrella becomes cooler on the outside and denser than the

surrounding air Supercells form within the updraught as well as precipitationFun Fact: Miller experimentFaulting: Sitting on an active secondary fault Mostly strike-slip faulting Possibly the cause of the eruption

Continuing Activity by August 2008:120 m Lava domeEarthquakes at summitBoulders avalanching into craterVolcano degassing/ash