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Chile earthquake and tsunami. Magnitude 8.8; hypocenter 21 miles. Tsunami. Deep-ocean Assessment and Reporting of Tsunami. Changed the planet’s axis by three inches. Chile: M 8.8 earthquake. Large mass of rock moved Nearby island uplifted 2 feet Steep sloping subduction zone

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chile earthquake and tsunami
Chile earthquake and tsunami

Magnitude 8.8; hypocenter 21 miles

Tsunami

changed the planet s axis by three inches
Changed the planet’s axis by three inches

Chile: M 8.8 earthquake

Large mass of rock moved

Nearby island uplifted 2 feet

Steep sloping subduction zone

Each day should be 1.26 microsecond shorter (hundredth of a second)

chile aftershocks
Chile: aftershocks

Magnitudes: 6, 5.1, 4.9

Tsunami warning

mitigation measures to reduce risk
Mitigation: measures to reduce risk
  • Understanding the potential hazards
  • Hazard maps
  • Monitoring
  • Emergency plan in place and practiced
  • Education of government officials and public
understanding the past
Understanding the Past
  • The eruptive history is very important.
  • Ancient volcanic deposits are dated to determine frequency of eruptions.
understanding of hazards provide definition and potential location
Understanding of hazards: provide definition and potential location
  • People will evacuate when there is an understanding of the potential destruction from a hazard.
disaster nevado del ruiz volcano columbia 1985
The people of Armero did not understand the potential hazards of a lahar

Government officials knew about the potential hazard

23,000 fatalities

Disaster Nevado del Ruiz volcano, Columbia, 1985
slide14

Map ancient volcanic deposits.

Hazard Map of Mt. Rainier: map indicates previous lahar and pyroclastic flows

Results: where one would expect these hazards to occur in the future

lassen peak hazard map
Lassen Peak, Hazard Map
  • Vents that have produced eruptions
  • Yellow- lava flow zones
  • Gold- ash fall zone
  • Orange-combined
  • Pink-mudflows
  • Aqua- floods
monitoring precursors
Monitoring Precursors
  • Physical changes are known to precede a volcanic eruption.
  • Name changes in volcanic activity. These changes are called precursors.
  • Seismicity
  • Deformation
  • Snow melt
  • Water levels and chemistry
  • Gas emission
  • Small eruptions
slide18

Monitoring VolcanoesGround Deformation

  • Movement of magma into the system tends to inflate the volcano’s surface
  • Tiltmeters
  • Global Positioning Stations (GPS)
  • Radar interferometry- satellite
slide19

Deformation

Tiltmeter

  • Direct measurements are made when the volcano is increasing in precursor activity

Global Positioning Satellites record vertical and horizontal movement of the volcano

slide20

Monitoring VolcanoesSeismicity

Mt. St. Helens

  • Magma fractures cooler rock causing earthquakes
  • An increase in the number of earthquakes may indicate an imminent eruption
slide21

Seismometer

  • Seismic waves move through the crust and reach the seismometer
  • The seismometer records the strength and type of movement
  • The information is sent to a station and recorded through radio waves or satellite communication

Seismometer placed near Mt. St. Helens

monitoring the long valley caldera
Monitoring the Long Valley Caldera
  • Ground deformation
  • Resurgent dome grew is 80 centimeters from the late 1970’s to 1999
  • minor subsidence since 1999
monitoring the long valley caldera23
Monitoring the Long Valley Caldera
  • Seismicity averages 5-10 earthquakes per day since 1999
  • Occasionally swarms of earthquakes cause alarm (200-300/week)
  • generally less than M=2
mt st helens
Mt. St. Helens
  • Seismic activity increased in 2005
  • Increased monitoring of activity
  • Seismicity
  • Visual inspections
  • Gas emissions
mt st helens27
Mt. St. Helens
  • Alert level 2: activity increasing that lead to a hazardous volcanic eruption
  • Aviation level orange- ash to 30,000 feet, traveling 100 miles
slide28

Seismicity

  • With more than three stations the initial rupture of the earthquake is located
  • Outlining the size and location of the magma chamber
mt st helens29
Mt. St Helens
  • Green dots represent activity in the past 24 hours.
slide30

Gas Emissions: as magma ascends, decompression melting releases gas

Sulfur dioxide cloud, three hours after eruption

  • Direct and indirect measurements
  • Increase in gas emissions may indicate an imminent eruption
mt st helens31
Mt. St. Helens

Volcanic watch

monitoring the long valley caldera32
Monitoring the Long Valley Caldera
  • Carbon dioxide escape from the magma chamber
  • Associated with faults that act as pathways
  • 50-150 tons per day since 1996
  • level remains the same
  • Horseshoe lake
slide33

Gas Emissions

  • Direct sampling is completed by collecting the gas in a liquid
  • Analysis is done at a laboratory
slide34
Satellite images can monitor movement of ash in the atmosphere. Ash abrades windows and can cause engine failure

Composite satellite image of ash produced from Mt. Spur, Alaska over a one week period

slide35

Thermal Change indicates magma moving closer to the surface

  • Satellite sensors are able to detect increased temperatures before an eruption
  • Used for remote active volcanoes or if seismicity does not precede an eruption

Pavlov Volcano, Alaska

lahar warning system
Lahar Warning System
  • Sensors detect high frequency vibrations produced by lahars moving down a stream channel
  • Sensors are placed downstream from volcano but upstream from population
warning system38
Warning System
  • Normal: Typical background activity; non-eruptive state
  • Advisory: Elevated unrest above known background activity
  • Watch: Heightened/escalating unrest with increased potential for eruptive activity
  • Warning: Highly hazardous eruption underway or imminent
aviation warning system
Aviation Warning System
  • Green: normal activity
  • Yellow: exhibiting signs of elevated unrest
  • Orange: heightened unrest with increased likelihood of eruption (specify ash plume height)
  • Red: eruption’s forecast to be imminent with significant emission of ash into the atmosphere (specify ash plume height)
communication
Communication

Most important: think of the disasters in the past 6 years

volcanic disaster assistance program43
Volcanic Disaster Assistance Program
  • The primary purpose is to save lives in developing countries.
  • Works with the Office of /Foreign disaster Assistance
  • U.S. Agency for International Development
volcanic disaster assistance program44
Volcanic Disaster Assistance Program
  • The Volcanic Disaster Assistance Program was developed after the 1985 eruption of Nevada del Ruiz.
  • Since 1986, the response team organized and operated by the U.S.G.S. responds globally to eminent probable volcanic eruptions.

Nevada del Ruiz lahar that

killed 23.000 people.

communication to public
Increase in seismic activity in 1996

Alaska

Prevent evacuation of 1,000 residents

Prevent closing of fishing industry

Communication to Public
the eruption of rabaul papua new guinea september 1994
The eruption of Rabaul, Papua New Guinea, September, 1994.
  • Residents who witnessed the 1937 eruption explained what occurred
  • Education of the local population through community groups
  • Successful evacuation due to following the plan
successful prediction
Successful Prediction
  • Mount Pinatubo, 1991

Approximately 330,000 people evacuated prior to the eruption

evaluation of risk
Evaluation of Risk
  • Zones of highest to lowest risk should be identified
  • Urban planning should take in account the areas of highest risk
  • These areas should be evacuated first
slide50
Risk
  • Applying the Volcano Explosivity Index
  • Mt. Pinatubo- 6-7
  • Amount of property damage
  • Population
  • This equates to the amount of risk
evaluation of volcanic risk
Evaluation of Volcanic Risk
  • United Nations Educational, Scientific and Cultural Organization-UNESCO
  • Risk=(value)x(vulnerability)x(hazard)
  • Value= # of lives, monetary goods in area
  • Vulnerability=% of lives or goods likely to be lost in a given event
  • Hazard=based on the Volcanic Explosivity Index- VEI
volcanic explosivity index
Volcanic Explosivity Index
  • Volume of material
  • Eruption column height
  • Eruptive style
  • How long the major eruptive burst lasted

Plinian: 5-7; 1993 Lascar Volcano, Chile

Hawaiian: 0-2

evaluation of risk54
Evaluation of Risk
  • Mt. Vesuvius produced a VEI 5 eruption in 79 CE.
  • There are now 3 million people living on and near this volcano.
  • Less than 1% chance for another eruption this size in the next 10 years
  • High risk coefficient due to the high population density

Mt. Vesuvius, Pliny

vesuvius erupts
Vesuvius Erupts
  • Computer simulations help understand which areas would be affected first
  • Those communities should be evacuated first
mt vesuvius areas of risk
Mt. Vesuvius, Areas of Risk

Emergency plan assumes that there can be a 20 day warning

without warning
Without warning
  • Estimated 15-20,000 casualties
  • What do you think?

1944 eruption

mitigation
Mitigation
  • Understanding the potential hazards
  • Hazard maps
  • Monitoring
  • Emergency plan in place and practiced
  • Education of government officials and public
  • Communication clear between scientists, government officials and the public