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 TYPHOONS FLOODS LANDSLIDES VOLCANIC ERUPTIONS GLOBAL CLIMATE CHANGE ENACT AND IMPLEMENT POLICIES HAVING HIGH BENEFIT/COST FOR COMMUNITY RESILIENCE GOAL: DISASTER RESILIENCE

PHILIPPINES’COMMUNITIESPHILIPPINES’COMMUNITIES DATA BASES AND INFORMATION HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS VOLCANO HAZARDS BLDG. INVENTORY VULNERABILITY LOCATION VOLCANO RISK RISK ACCEPTABLE RISK UNACCEPTABLE RISK GOAL: EARTHQUAKE DISASTER RESILIENCE PREPAREDNESS PROTECTION EARLY WARNING EMERGENCY RESPONSE RECOVERY and RECONSTRUCTION POLICY OPTIONS

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

LATERAL BLAST VOLCANIC ERUPTIONS VOLCANIC ERUPTIONS PYROCLASTIC FLOWS FLYING DEBRIS VOLCANIC ASH LAVA FLOWS LAHARS TOXIC GASES CAUSES OF RISK CASE HISTORIES

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

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

MOUNT PINATUBO FACTS Pinatubo is a stratovolcano, a volcano comprised of layers of lava flows and pyroclastic material that gradually accumulated over time.

ANCIENT MOUNT PINATUBO Ancestral Pinatubo was an andesite and dacite stratovolcano whose center was in roughly the same location as the modern Pinatubo.

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.

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. ERUPTION HISTORY

. 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.

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.

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 SO 2 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.

EARLY WARNING AND EVACUATION FACTS

–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). EARLY WARNINGS WERE SUCCESSFUL

EVACUATION PHIVOLCS and USGS developed three evacuation zones

EVACUATION ZONES

EVACUATION The 10 km and km zones contained 40,000 people The 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

Wednesday, 8:15 AM June 12, 1991 : : EVACUATION HAPPENED BEFORE DAY TURNED TO NIGHT

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, Nearly 9 m of sediment were deposited during a single lahar event on August 15, 1991

AFTER THE ERUPTION Sacobia Bamban River

The Climactic Eruption This was the second largest eruption on Earth in the 20 th 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 decreased by °C 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.

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 eco- tourism destination Mt. Pinatubo, 2013

POLICY ADOPTION RISK ASSESSMENT VULNERABILITYVULNERABILITY EXPOSUREEXPOSURE EVENTEVENT POLICY ASSESSMENT COSTCOST BENEFITBENEFIT CONSEQUENCESCONSEQUENCES TOWARDS DISASTER RISK REDUCTION FOR VOLCANOES VOLCANIC ERUPTIONS EXPECTED LOSS

MONITORING TECHNOLOGIES AND WARNING SYSTEMS ARE A VITAL PART OF SURVIVAL.

MONITORING TECHNOLOGIES.