Valena Berry and Rachel Valena 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 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 6 th of May.

 May 2 nd : Government declared state of emergency and evacuated several hundred people from the town of Chaitén 6.21 miles SE of the volcano.  May 3 rd through the 6 th : reported 4,000 to 5,000 people evacuated from Chaitén and surrounding area.  May 5 th : 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.  24 th 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 27 th and 28 th, 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 pastures  Skin Fungal infections  Accelerated wear on teeth and gums  Government provided farm-recovery funds

Structural Damage  Urban and Rural Communities:  Individual town: Futeleufú  300mm ash (11.81 inches)  Disrupted water, electricity, transportation, and telecommunication.  Residential/commercial damage:  Gutters  Roof cladding corrosion  Structural roof damage  Internal ash contamination  Hydro-electric dams  Bridges destroyed by lahars Aviation  Mass flight cancellations  Closed airports  Ash in airspace weeks after  Turbine 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 precipitation Fun Fact: Miller experiment Faulting:  Sitting on an active secondary fault  Mostly strike-slip faulting  Possibly the cause of the eruption

Continuing Activity by August 2008:  120 m Lava dome  Earthquakes at summit  Boulders avalanching into crater  Volcano degassing/ash