Volcanic Hazard Maps (Lesson 5.1/Week 8) PDF
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Asia Pacific College
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This document is about volcanic hazard maps and related topics. It includes information on different types of volcano hazard maps, how to use them for evacuation planning, and the meaning of volcano alert levels. The document also touches upon volcanic eruptions, their impacts, and monitoring.
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Asia Pacific College 3 Humabon Place, Magallanes Makati City www.apc.edu.ph D.R.R.R Volcanic Hazard Maps (Lesson 5.1/Week 8) At the end of the lesson, the learners will be able to: identify the different types of volcano hazard maps; demonstrate how to use the differen...
Asia Pacific College 3 Humabon Place, Magallanes Makati City www.apc.edu.ph D.R.R.R Volcanic Hazard Maps (Lesson 5.1/Week 8) At the end of the lesson, the learners will be able to: identify the different types of volcano hazard maps; demonstrate how to use the different volcano hazard maps for evacuation planning; and explain what Volcano Alert Levels mean determine terms related to volcanic eruption NEWS ALERT! Mayon Volcano Volcano Alert Levels VOLCANIC HAZARDS ✓ LAVA FLOWS ✓ PYROCLASTIC FLOWS & SURGES ✓ ASHFALL OR TEPHRA FALL ✓ LAHARS ✓ VOLCANIC GASES ✓ GROUND FISSURING ✓ DEBRIS AVALANCHE ASHFALL or TEPHRA FALL ✓ Gravitational settling of volcanic ash & fragments from the umbrella clouds of tall eruption columns & ash clouds of pyroclastic flows ✓ Dispersal depends on prevalent wind directions, column heights IMPACTS OF ASH FALL ✓ Results to widespread infrastructural damages when thick ✓ Monitored worldwide by aviation agencies because ashfall can cause potential jet engine failure to all types of aircraft LAVA FLOW ✓ Incandescent rivers of hot molten rock (lava) ✓ Erupted from volcanic craters, fissures, during Hawaiian- Strombolian activity, lava dome eruptions ✓ Usually slow-moving for moderate-high SiO2 magma ✓ fast- moving for low SiO2 magma (e.g. Hawaii lavas) 1969 TAAL VOLCANO (MT. TABARO) LAVA FLOW FIELD 1993 Mayon lava flow IMPACTS OF LAVA FLOW ✓Main hazard of burial, generation of deadlier pyroclastic flows ✓Results in long term disuse of buried land! PYROCLASTIC FLOWS & SURGES ✓ Turbulent mass of ejected fragmented volcanic materials (ash & rocks) + hot gases that flow downslope at very high speeds (> 60 kph) ✓ Deadliest of all volcanic hazards IMPACTS OF PYROCLASTIC FLOW AND SURGE Ridge Ridge LAHARS ✓ Rapidly flowing thick mixture of volcanic sediments and water ✓ Triggered by rainfall, melting of craterial icecaps, lake breakout or hydrothermal “squeezing” TWO CLASSES OF LAHARS IMPACTS OF LAHARS Burial Cutoff and Isolation Long-term siltation & related flooding Gases ✓ Basic components of magma or lava (H2O, CO2, CO, H2S, F2, SO2, H2SO4, etc.) ✓ Mostly toxic species BUBBLING OF WATER DURING 1969 ERUPTION, TAAL LAKE, DUE TO ESCAPING GAS FROM MAGMA BENEATH THE LAKE FLOOR GROUND FISSURING ✓ due to movement of magma beneath the surface may be movement / adjustments along faults accompanied by earthquakes DEBRIS AVALANCHE ✓ Downslope movement of large-volume proportions of the volcanic flanks due to: ❑ movement of magma beneath the edifice (Bezymmiany-type) ❑ adjustments along faults transecting volcanoes ❑ earthquakes (Bandai- type) FOR 8-10 GIVE 3 VOLCANIC HAZARDS MAYON VOLCANO HAS EXHIBITED FOR THE PAST 100 YEARS. SPECIFY THE VOLCANIC HAZARD AND THE YEAR OF OCCURENCE (SHOULD BE BASED ON OUR DISCUSSION YESTERDAY). FOLLOW THIS FORMAT (NO SPACING PLS!): EXAMPLE: LAHAR/2003 VOLCANO MONITORING Station maintenance at Veniaminof Volcano, Alaska. VOLCANO-GEOLOGIC MAPPING VOLCANIC HAZARDS MODELING INFORMATION DISSEMINATION & WARNING Mitigation of Volcanic Hazards in the Community EDUCATING THE COMMUNITY ON ERUPTION RESPONSE EDUCATING THE COMMUNITY ON ERUPTION RESPONSE HOW DOES THE PHILIPPINES PREPARE FOR THE POSSIBLE VOLCANIC ERUPTIONS?
