Background Information

• Population approx 105 million (2018) - densely populated around coastlines due to mountainous terrain

• Capital city Manilla (not affected by volcano)

• Archipelago of volcanic islands located in the Pacific Ocean in East Asia

• LIDC (cusp of EDC) - very reliant on primary industry - fishing, agriculture

• Tectonically active location - regularly affected by devastating typhoons

• June 1991 - erupted over a few weeks in June

Cause

• Subduction plate boundary - magma rises to surface as denser oceanic plate subducted below a less dense tectonic plate

• Causes explosive volcanic eruptions - viscous basaltic lava - results in formation of steep sided strato-volcanoes (composite)

• Caused pyroclastic flows - travelled at 80km/h - reached 5km - created ash clouds (12km³ of rock and ash) up to 40km into the air

• Winds carried ash 100’s of km

Effects

• Cloud of ash and debris (tephra cloud) send up to 30km high by explosion

• Ash fell 50cm deep in immediate area - 10cm to 600km radius

• Approx 700 people died - many due to secondary effects - suffocation in lahars, disease, food shortages

• 184 injured

• 1.8 million people affected

• 200,000 houses and public buildings collapsed due to weight of ash deposits and fast moving lahars

• At least 650,000 jobs lost - destruction of farms, shops, factories

• Significant loss of crops for 2 years - planting was impossible the following year - long term food shortage

• Longer term - ash would have added nutrients to soil and increased productivity

• Over 1 million animals died - lack of food due to ash that fell on the ground

• Global dimming (volcanic winter) caused by ash cloud - sulphur particles reflecting suns rays

• Winter in UK and across northern hemisphere estimated 0.5°C cooler

• Eruption estimated to have cost $700 million - $100 million damage to aircraft flying at time of eruption

• Total cost estimated $10 billion

Mitigation

• Evacuation orders issued for area as soon as activity was detected - several weeks before eruption

• 5th April - villages within 10km summit evacuated

• 12th April - evacuation area extended to 30km and 200,000 people evacuated

• Approx 20,000 local residents did evacuate - BUT many people protecting their land - livelihood was more important - chose not to leave

• Others experienced evacuation orders before - false alarms - chose not to leave

• Some Aeta people refused to leave the mountain - lack of understanding about eruption - strong sense of community

• US army successfully evacuated 15,000 people from Clark airbase

• Total cost of evacuation - approx $93 million

• Many evacuees were migrants to the area - chosen not to return

• Air space closed - mitigate risk of further disaster in area used by military personnel as well as domestic cargo flights

• $100 million damage to planes due to increased level of ash in atmosphere surrounding immediate area

Responses

• At the time largest volcanic disaster in a populated area - responses were appropriate to scale of disaster

• NGO’s such as Oxfam and Red Cross provided emergence aid - food, water, blankets, and tents as well as medical aid

• Engineers build dams and dikes to stop lahars (mud flows)

• Camps built to resettle people whose land and buildings were destroyed - as late as 2005 people were still living in these