Transcript volcanic eruptions

LESSONS LEARNED FROM
PAST NOTABLE DISASTERS.
THE PHILIPPINES.
PART 3: VOLCANIC
ERUPTIONS
Walter Hays, Global Alliance for
Disaster Reduction, Vienna,
Virginia, USA
NATURAL HAZARDS THAT PLACE THE
PHILIPPINES’ COMMUNITIES AT RISK
EARTHQUAKES
GOAL: DISASTER
RESILIENCE
ENACT AND IMPLEMENT
POLICIES HAVING HIGH
BENEFIT/COST FOR
COMMUNITY RESILIENCE
TYPHOONS
FLOODS
LANDSLIDES
VOLCANIC ERUPTIONS
GLOBAL CLIMATE CHANGE
VOLCANO RISK
•VOLCANO HAZARDS
•BLDG. INVENTORY
•VULNERABILITY
•LOCATION
DATA BASES
AND INFORMATION
ACCEPTABLE RISK
RISK
UNACCEPTABLE RISK
PHILIPPINES’
GOAL: EARTHQUAKE
DISASTER RESILIENCE
COMMUNITIES
POLICY OPTIONS
HAZARDS:
GROUND SHAKING
GROUND FAILURE
SURFACE FAULTING
TECTONIC DEFORMATION
TSUNAMI RUN UP
AFTERSHOCKS
• PREPAREDNESS
•PROTECTION
•EARLY WARNING
•EMERGENCY RESPONSE
•RECOVERY and
RECONSTRUCTION
THE KEYS TO RESILIENCE:
1) KNOW THE ERUPTIVE HISTORY OF
YOUR REGION’S VOLCANOES,
2) BE PREPARED
3) HAVE A WARNING SYSTEM
4) EVACUATE
5) LEARN FROM THE
EXPERIENCE AND START OVER
CAUSES
OF RISK
LATERAL BLAST
PYROCLASTIC FLOWS
FLYING DEBRIS
VOLCANIC
ERUPTIONS
CASE HISTORIES
VOLCANIC ASH
LAVA FLOWS
LAHARS
TOXIC GASES
THE PHILIPPINE PLATE
VOLCANOES
VOLCANOES HAVE ERUPTED VIOLENTLY
IN THE PHILIPPINES AS A RESULT OF
COMPLEX INTERACTIONS OF THE
PHILIPPINE AND EURASIAN PLATES
GLOBAL DISTRIBUTION OF 1,500
ACTIVE VOLCANOES
http://www.cia.gov/cia/publications/factbook/geos/rp.html
LUZON VOLCANIC ARC
Chain of subduction volcanoes on the
west side of the Philippine island of
Luzon, including Mount Pinatubo
red triangles = volcanoes active
in the last 10,000 years
Major Volcanoes in
the Philippines
http://vulcan.wr.usgs.gov/Volcanoes/Philippines/Maps/map_philippines_volcanoes.html
MOUNT PINATUBO FACTS
• Pinatubo is a stratovolcano,
a volcano comprised of
layers of lava flows and
pyroclastic material that
gradually accumulated over
time.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
ANCIENT MOUNT PINATUBO
Ancestral Pinatubo was an andesite and
dacite stratovolcano whose center was
in roughly the same location as the
modern Pinatubo.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
MOUNT PINATUBO FACTS
–Before April 2, 1991,
volcanologists considered
Mount Pinatubo to be an
inconspicuous, currently
inactive volcano that had
once been active a
millennium ago.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
ERUPTION HISTORY
• The largest prior eruption in the
history of the modern Pinatubo
occurred over 35,000 years ago.
• That eruption distributed over 325
ft (100 m) of pyroclastic flow
material on all sides of the volcano,
signaling the geologic rebirth of the
volcano.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
ERUPTION HISTORY
.
• Radiocarbon ages suggest that
eruptions from the modern
Pinatubo have been clustered in at
least six and possibly as many as a
dozen eruption episodes.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
MOUNT PINATUBO FACTS
–Many people residing in the
area, including those in
nearby military bases,
barely knew of Mount
Pinatubo at allm a factor
that hindered evacuation.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
VOLCANO HAZARDS
CAN HAVE FAR REACHING IMPACTS
• VERTICAL PLUME (can affect
jet aircraft)
• ASH AND TEPHRA
• LATERAL BLAST
• PYROCLASTIC CLOUDS,
BURSTS, AND FLOWS
VOLCANO HAZARDS
CAN HAVE FAR REACHING IMPACTS
• LAVA FLOWS
• LAHARS (can bury villages)
• EARTHQUAKES (related to
movement of lava)
• “VOLCANIC WINTER” (causing
famine and mass extinctions)
THE PHILIPPINES’ MOST
NOTABLE VOLCANIC
ERUPTION
MOUNT PINATUBO
JUNE 7, 1991
TIME LINE 1
• On July 16, 1990, a 7.8 magnitude
earthquake hit central Luzon. Its
epicenter was 100 km NE of Mt.
Pinatubo
• On March 15, 1991, a series of
earthquakes took place on the NW
side of Mt. Pinatubo
TIME LINE 2
• The earthquakes continued to
increase in intensity for 2 weeks
• On April 2, 1991, small eruptions
began. Hundreds of small
earthquakes were recorded every
day.
MT. PINATUBO: April 1991
TIME LINE 3
• SO2 emission increased from 500
tons/day on May 13 to 5,000
tons/day on May 28
• The first magmatic eruptions
occurred on June 3
TIME LINE 4
• The first explosion on June 7
generated a column of ash 7 km
high
• The Philippine Institute of
Volcanology and Seismology
(PHIVOLCS) issued a warning
predicting an eruption within 2
weeks
The
Eruption
of
Mount
Pinatubo
June 15, 1991
Luzon, Philippines
SNAPSHOTS IN TIME
BEFORE, DURING, AND
AFTER THE HISTORIC
ERUPTION
MOUNT PINATUBO FACTS
• Pinatubo had an elevation of 5725
ft (1745 m) above sea level before
the June 1991 eruption, and an
elevation of 5248 ft (1600 m) above
sea level after the June 1991
eruption.
http://volcano.und.nodak.edu/vwdocs/volc_images/southeast_asia/philippines/pinatubo.html
EARLY WARNING AND
EVACUATION FACTS
EARLY WARNINGS WERE SUCCESSFUL
– Warnings issued by PVO (Pinatubo
Volcano Observatory) before the
eruption succeeded in saving many
lives and protecting property.
– Warning issued by Civil Defense and
local officials saved lives.
– Warnings issued by PHILVOCS and
USGS led to total evacuation of Clark
Air force Base (including aircraft).
EVACUATION
• PHIVOLCS
and USGS
developed
three
evacuation
zones
EVACUATION ZONES
EVACUATION
• The 10 km and
10-20 km zones
contained 40,000
people
• The 20-40 km
zone contained
331,000 people
• A volcanic alert
system was
developed, with
daily updates
EVACUATION
• Evacuation
began:
–10 km zone on
April 7
–10-20 km zone
on June 7
–20-40 km zone
on June 14
The Climactic Eruption
• Large tremors began at 13:42 on June 15
• By 14:30 all seismographs were inoperative
• The most violent phase lasted 3 hours and
generated a 34 km high eruption column
• The ash cloud covered 50,000 sq. miles
EVACUATION HAPPENED BEFORE DAY
TURNED TO NIGHT
•

Wednesday,
:
8:15 AM June 12, 1991
A 34-KM-HIGH ERUPTION
COLUMN
The Climactic Eruption
• Typhoon Yunga hit Lazon on the
same day, obscuring direct view
• The eruption ended 9 hours later
at 22:30
MT. PINATUBO: JUNE 15, 1991
VIEW OF PINATUBO AFTER THE
ERUPTION
Mount Pinatubo, as seen from Clark Air Base runway
AFTER THE ERUPTION
O’Donnell River
AFTER THE ERUPTION
A house by the Sacobia-Bamban River, Bamban, Tarlac, July 23, 1991.
Nearly 9 m of sediment were deposited during a single lahar event on August 15, 1991
A house by the Sacobia-Bamban River, Bamban, Tarlac, July 23, 1991.
AFTER THE ERUPTION
Sacobia Bamban River
The Climactic Eruption
• This was the second largest eruption on Earth in
the 20th century; Volcanic Explosivity Index of 6
• Expelled: 10
billion tons of magma and
20 billion tons of sulfur dioxide (SO2)
IMPACTS
LOCAL IMPACTS
• In the first three
months after the
enormous eruption,
>200 lahars occurred
• About 300 people
were killed, mostly by
roofs collapsing
under wet ash
• 364 communities and
2.1 million people
were impacted
School buried by lahar,
Church buried by lahar
LOCAL IMPACTS
• >8,000 homes
completely destroyed
• Pyroclastic flows
filled river valleys
with hot volcanic
rocks, which killed
vegetation and
rendered land infertile
• The GDP fell by 3% in
1991
• Every rainy season,
lahars return
School buried by lahar
Church buried by lahar
GLOBAL IMPACTS
• This was the
largest injection
of aerosols into
the stratosphere
ever recorded
by modern
instruments
SAGE II observations show that aerosols in the
tropics increased by almost a factor of 100
immediately following the eruption, spread to the
Earth’s mid-latitudes three months later, and slowly
decreased over several years.
GLOBAL IMPACTS
• Aerosols formed a
stratospheric cloud
which reduced
sunlight reaching the
Earth’s surface by up
to 5% for 3 years
• Northern hemisphere
average
temperatures
SAGE II observations show that aerosols in the
tropics increased by almost a factor of 100
decreased by
immediately following the eruption, spread to the
Earth’s mid-latitudes three months later, and slowly
0.5-0.6 °C
decreased over several years.
SUMMARY
• The evacuation effort organized
by PHIVOLCS and USGS saved
tens of thousands of lives
• This was a great success for
volcanology and the prediction
of volcanic eruptions
• The indigeneous Aeta people
were hardest hit; many were
relocated permanently
• Mt. Pinatubo is now
a popular ecotourism destination
Mt. Pinatubo, 2013
TOWARDS DISASTER RISK
REDUCTION FOR VOLCANOES
RISK ASSESSMENT
• VULNERABILITY
• COST
• EXPOSURE
VOLCANIC
ERUPTIONS
• EVENT
EXPECTED
LOSS
• BENEFIT
•CONSEQUENCES
POLICY ASSESSMENT
POLICY
ADOPTION
MONITORING TECHNOLOGIES
AND WARNING SYSTEMS ARE
A VITAL PART OF SURVIVAL.
MONITORING TECHNOLOGIES
.