Krakatau Volcano, Sunda Strait, VEI 6 (Plinian), erupted August 1883,
- Exploded, creating a 37m tsunami wave that destroyed 295 towns and villages and killed 36,417.
- Pyroclastic flows followed the 2nd explosion and destroyed nearby towns before the major explosion.
- The tsunami only affected parts of Indonesia but the waves were detected in California.
- It carried a warship 3km inland, deposited 10 m above sea level, entire towns were swept away.
- The island was blown apart, the underwater magma chamber flood leaving 3 smaller islands.
- News of the event reached London in 12 hours due to the telegram.
Tambora Volcano, Indonesia, VEI 7 (Ultra plinian), erupted 1815
- Indonesia has a GDP per person of $11,000 and a population of 250 million.
- The first eruption lasted for 2 hours, the second lasted for 3: the pyroclastic explosion reach 43km up.
- The pyroclastic flow destroyed Sanggar and Tambora and created a 4m wave as it flowed into the sea.
- 50㎦ of lava erupted.
- Ash on the eastern tip of Java formed a 23cm layer and areas within 600 km were pitch black for 2 days, air temperature also lowered dramatically.
- The volcano collapsed from 4km high to 2.8km, the caldera formed is 6 km wide and 1 km deep.
- More than 10,000 people were killed initially and upwards of 60,000 died as refugees.
- 6Tg sulphur in the stratosphere caused temporary global dimming and the local temperature to drop.
Mount Pinatubo, Philippines, VEI 6 (Plinian), erupted 1991
- The Philippines have a GDP per person of $6,300 and a population of 102 million. Of the 7,100 islands, only 1,000 are inhabited. Most people live on the coast and there are 4 million slum dwellers in Manila.
- The main danger was lahar created by 3 inches of rain in a day from a typhoon mixing with pyroclasts and unconsolidated mud, flowing at around 40m/h and destroying over 100,000 homes and with 100,000 people in Luzon remaining vulnerable. 5㎦ of lava erupted.
- PHIVOLCS and the USGS teamed up quickly to evacuate over 60,000 people and $15m of military equipment of which 847 died. 600,000 jobs were lost and 1.2m people made homeless.
- Now, PHIVOLCS have a network of seismographs and river flow monitors to detect volcanic activity early and contact the emergency services instantly.
- Increased safety has lead to in-migration whereas PHIVOLCS were hoping ban living on the island.
Mount Kilauea, HA, VEI 0 (Hawaiian)
- Shield volcano, 1.2km high making up 14% of the Big Island, erupting constantly. The summit contains a lake that is home to the native Hawaiian goddess, Pele.
- Followers of native Hawaiian tradition idolise the volcano and believe in living close to it.
- The chain of volcanoes is a hotspot on the Pacific plate that is moving northward by 2 cm/year.
- 200 buildings have been destroyed by the eruption since 1983, over 100 occurred in one summer as the Royal Gardens were largely submerged.
Mount Saint Helens, WA, VEI 5 (Plinian), erupted 1980
- Juan de Fuca plate subducting under the North American plate.
- Main problem was the heat which melted snow causing flooding and lahars that killed animals up to 25 km away. 185 miles of highway, 250 buildings, 47 bridges and 15 miles of rail were destroyed, 57 deaths.
- The mudflow killed 12 million salmon in Spirit Lake and every tree within 30km was flattened
- The volcano exploded becoming 400m smaller creating 15 cm of ash fall. The ash did £100m of damage to machinery and cars, flights were cancelled, telephone lines went out and tourism died down.
- Small ash and steam eruptions had occurred since March, a bulge in the volcano was detected but volcanologists couldn’t predict the explosion so the exclusion zone was useless and some people refused to evacuate.
- The total federal cost of rebuilding, compensating and cleaning up was $960m.
Nevado del Ruiz, Colombia, VEI 3 (Vulcanian), erupted 1985
- Colombia have a GDP per person of approximately $7,500, at the time there was a recession.
- Nazca plate subducting under the South American plate, the Andes are created and Nevado del Ruiz is in the Andes.
- Snow at the top of the mountain melted due to the heat mixing with pyroclasts and mud creating lahar flows up to 50m wide and pyroclastic flows up to 100m wide flowing at up to 45m/h.
- The flows killed 26,800 people, £40m worth of claims were filed against the government for failing to defend.
Mount Nyiragongo, DRC, VEI 1 (Strombolian), erupted 2002
- The DRC had a GDP per person of $175 (below the poverty line) at the time, after a huge recession.
- The volcano is created by the East African Rift Valley diverging so the lava is basaltic.
- 14 villages were destroyed by lava flows up to 2m deep, 80% of the buildings in the town of Goma were destroyed (300,000 fled to Rwanda), 45 people died and several hundred were injured.
- Sulphur from the volcano poisoned a lake, killing the fish and rendering the main water source useless. The tourist industry also collapsed and there was a local economic recession.
The Siberian Traps (Lava Plateau), Northern Pangea
- Widespread volcanic eruptions about 250ma ago lasting for around 60,000 years.
- The lava is mostly basaltic, each event could have lasted decades erupting 2,000㎦ at a time. Dolerite, gabbro and pyroclastic rocks are also found indicating some explosions.
- Each flow could bury the UK in 6m of lava but the estimated total 3,000,000㎦ of lava erupted could’ve buried western Europe in 1km.
- The eruptions would’ve killed any life in the area, the ash produced caused global dimming, sulfur in the stratosphere caused global cooling and the result was likely the Permian mass extinction, killing around 97% of all living organisms.
Sichuan Earthquake, China, 2008, 8 on Richter, 7.9 on the Mercalli Scale
- At the time China had a GDP per person of $7,500.
- Longmenshan (thrust) fault where the Eurasian plate subsides under the Indian plate, a 10 km deep earthquake occurred 80km WNW of Chengdu in the early afternoon lasting 3 minutes and killing 70,000 people, (19th most deadly on record), injuring 374,000, making 4.8 million homeless, costing $146m.
- 5 million buildings (including 7,000 schools) collapsed. In Beichuan (rural, near epicentre) 80% of the buildings collapsed.
- An earthquake in 1976 has increased the readiness: necessities and shelter were sent out, the army and volunteers searched for survivors.
- The Zipingpu dam exerts the stress of 315m tonnes of water on an tectonically sensitive area.
- Landslides accounted for approximately 33% of the deaths and filled reservoirs causing some flooding.
Darfield Earthquake/Lyttelton Aftershock, NZ, 2010/11, Magnitude 7.1/6.3
- New Zealand has a GDP per person of $37,000. It sits on a transform fault and 2 convergent boundaries where the Australasian and Pacific oceanic plates are subducting under the continental plates of the same name.
- The focus was 10km down (shallow) and the epicentre was 40km west of Christchurch. A 24 km fault was created. Unknown underground faults transmitted energy further than usual.
- The aftershock end occurred 5km from Christchurch’s CBD, killing 182.
- Significant liquefaction ‘flooded’ entire streets. Buildings and 80% of pipes were destroyed, £8bn of damage was done.
- Businesses set up quickly in new locations, the Canterbury Earthquake Recovery Authority oversaw 5 years of reconstruction.
- Existing buildings were meant to survive a 1 in 250 year event but the earthquake was a 1 in 2,500 year event. 10,000 buildings had to be demolished, 100,000 were repaired.
- School children were quickly relocated.
Haiti Earthquake, 2010, Magnitude 7
- Haiti is the least developed country in the western hemisphere, GDP per person of $1,500 in 2010. 70% of the population are below the poverty line. The last major earthquake (Enriquillo fault) was in 1770.
- The earthquake was only 2-8km deep
- 2.5m people live in Port au Prince, the capital. 222,000 were killed in the initial quake, 70-80% of buildings were destroyed and 1.5m people were made homeless. $7.8bn of damage (120% of GDP).
- The epicentre, Leogane (15km SW of the capital), lost 80-90% of it’s buildings.
- Building quality was poor: brittle steel, cement containing salt and shortage of steel rods.
- 800,000 people had to live in camps, only 40% had shelter. The main port and telephone lines were destroyed. ⅓ of the victims were buried in mass graves but diseases like cholera spread easily.
- Refugees in the Dominican Republic overwhelmed services, the US sent 5,500 troops and 6 ships who reopened the port, celebrities raised £35m, the UN and the World Food Programme appealed for donations to supply food for 3m for 6 months.
- The World Bank cancelled debts of $36m owed by Haiti and 53% of $5.5bn was contributed internationally to redevelop (stronger buildings, rehousing the homeless).
- A year later, 500,000 people are still in camps, 60% of buildings remain damaged and political corruption is slowing down redevelopment despite money available.
Asian Tsunami, 2005, 9 on the Richter Scale
- Subduction of the Indian plate under the Sunda plate creates a thrust fault with andesitic volcanoes.
- Friction caused by subduction dragged the hanging wall down until it sprang back up creating a 400km fault in ~200 seconds.
- The tsunami wave reached Indonesia, where it did the most damage, in 45 minutes.
- An area 400 km by 100km and approximately 3m high of water was displaced.
- Waves peaked at 10m in Sumatra, bores were created in river channels and the surge carried debris.
- The surge which carried the debris was destructive for the mostly non-structural buildings.
- 250,000+ people died and 2m people lost their homes.
- Water purification tablets and temporary housing was donated from abroad.
- The Maldives, of which 74% of it’s GDP is from tourism, suffered a 10% recession.
- An early warning system of seismometers has been set up.
Tohoku Tsunami, Japan, 2011, 7.2 on the Richter Scale
- Subduction of the Pacific plate under Japan on the edge of the Eurasian plate creates a thrust fault.
- A magnitude 9 earthquake occurred when 480 km of plate broke free.
- The earthquake caused a 40m tsunami that reached Japan in 10 minutes reaching 10 km inland.
- 15,676 people died, 5,712 were injured and 4,832 went missing. Victims were predominantly the elderly.
- 425,000 people were living in inadequate emergency accommodation leading to hypothermia, the Sendai airport was destroyed which delayed aid.
- Medical supplies were short, transport was difficult and communication was mostly destroyed.
- 45,700 buildings were completely destroyed along with 11 hospitals.
- Around 200,000 people were evacuated from the area surrounding Fukushima.