Volcanoes, Earthquakes and Tsunamis as Geo-Hazard Concerns in the Island of Mindanao

Renato U. Solidum Jr and Ma. Mylene M. Villegas Philippine Institute of Volcanology and Seismology

Department of Science and Technology

The Mindanao Summit on Disaster Risk Reduction and Geo-Hazard Awareness

Cagayan de Oro City, February 18, 2012

Hazards

NATURAL HAZARDS

Geologic Hydro-meteorologic

• Volcanic eruptions Typhoons • Earthquakes Strong wind • Tsunamis Storm surge Landslides/mudflows Floods/flashfloods Erosion Drought, desertification Ground subsidence Extreme temperature warming, cooling Sea level change Salt-water intrusion

- threat that can cause loss of life, injury, property damage, loss of livelihood or services, social and economic disruption

1991 Explosive Eruption of Pinatubo: Can a similar eruption happen in Mindanao?

Tall eruption columns Pyroclastic flows downslopes at speeds >60kph

Thick ashfall caused collapse of roofs

Post-eruption lahars burying villages

Answer - YES

Volcanoes in

Mindanao

• 8 active volcanoes (erupted within the last 10,000 years)

Mt Parker – South Cotabato

Mt Parker Crater Lake

• Mt. Parker last erupted in 1641 • eruptions are similar to Mt. Pinatubo

Hazard Map of Mt. Parker

Active volcanoes in Mindanao

(eruption in the last 10,000 years) Name No. of Last eruption Location

Eruption Hibok-hibok 5 1949-1953 Camiguin

Ragang 7 1916 Lanao

Bud Daju 2 1897 Sulu

Musuan 1 1866 Bukidnon

Matutum 1 1911 S. Cotabato

Parker 1 1641 S. Cotabato

Makaturing 7 1882 Lanao

Leonard 1 1800 yrs ago Davao del N

Hibok-hibok 1951 eruption killed >500 people

Destructive Earthquakes: Can this happen in Mindanao?

Answer - YES

Magnitude 6.9

Negros

Earthquake

Liquefaction

Landslide

Collapse of Buildings – Intensity VIII

Earthquake Activity in Mindanao

Earthquake Generators and

Liquefaction Prone Areas in

Mindanao:

Active Faults (Red) Trenches (Violet)

Liquefaction (Yellow)

Earthquake-

triggered

Landslide

Hazard Map of

Mindanao

Large Tsunamis: Can these happen in Mindanao?

Miyako City

Natori City

From AP

From Kyodo News

Answer - YES

March 11, 2011

Japan Tsunami

Kessenuma From RUSolidum, PHIVOLCS

August 1976 Moro Gulf M7.9 Earthquake & Tsunami

Scope: Southwest Mindanao Casualties: Dead – 3,792 Missing – 1,937 Injured – 9,240 Houses Damaged: Total – 60,356 Estimated total damage: PhP 2.47 B

• Magnitude

7.9 quake

• Maximum

tsunami height

9 meters

Inundated villages Damaged houses & buildings

Transported bancas Crushed vehicles

Tsunami Impacts: 1976 August Earthquake

Tsunami causing earthquakes and tsunami events in eastern Mindanao

•1921 November 11 (Ms 7.4) •1924 April 14 (Ms 8.3) •1929 June 13 (Ms 7.2) •1952 March 19 (Ms 7.6) •1992 May 17 (Ms 7.1)

1921

1924

1929

1952

1992

Five (5) tsunami events 1 – 5 m high

One (1) tsunami event 6 m high

•1897 Sept 21 (Ms 7.5) 1897

Tsunami causing earthquake and tsunami event in northwestern Mindanao

•1917 January 31 (Ms 6.4) •1918 August 15 (Ms 8.0) •1923 March 2 (Ms7.2) •1976 August 17 (Ms 8.0) •2002 March 2 (Ms 6.8)

1917

1918

1923

1976

2002

Five (5) tsunami events 1 – 9 m high

Tsunami causing earthquakes and tsunami events in southern Mindanao

Tsunami Hazard Map – Davao Oriental

Tsunami Hazard Maps for Mindanao

Tsunami Hazard Map – Sultan Kudarat

Liquefaction Hazard Map

Surigao del Norte

Summary

• Moderate-sized to large explosive volcanic eruptions happened and can happen again in Mindanao

• Large-magnitude and destructive earthquakes happened and can happen again in Mindanao

• Large tsunamis happened and can happen again in Mindanao

• Explosive eruptions, destructive earthquakes and tsunamis are concerns that Mindanao should prepare for

Sudden onset, Infrequent events, Most often, destructive Let us focus on awareness raising Let us prepare communities

Please visit PHIVOLCS-DOST

booth

www.phivolcs.dost.gov.ph

For more info on geologic hazards maps, awareness and preparedness materials