Tectonic Hazards + DRM

Ground shaking examples

1. 2010 Haiti earthquake (Mw 7.0)

   • Surrounding areas around factories were polluted

   • Debris polluted rivers

   • More than 250000 houses collapsed due to violent virations

   • About 220000 people were killed

   • water pipes ruptured causing water shortages

2. 2010 Christchuch New Zealand earthquakes:

   • Many trees were damaged and more than 300 had to be removed reducing availability of habitat for terrestrial species

Soil liquefaction examples

1. 2010-2011 Christchurch New Zealand earthquakes

   • Triggered severe liquefaction as the city lies on a former swamp area where soils are loose and saturated

   • More than 60000 residential buildings and infrastructure covering about 1/3 of the city area were damaged

   • Liquefied soil entered rivers, and untreated sewage from broken pipes polluted rivers.

   • This resulted in the reduction of some species such as the caddisflies

Landslide examples (mainly use debris)

1. 2018 Papua New Guinea earthquake (Mw 7.5)

   • Triggered landslides that cause huge amount of debris to enter the rivers

   • Caused flooding

   • Destroyed forests

   • Polluted waters and killed fish

2. 2008 Great Sichuan China Earthquake (Mw 7.9)

   • Triggered more than 15000 landslides

   • Destroyed many buildings and infrastructure

   • Caused nearly 20000 deaths

How do Tsunamis occur

1. An undersea earthquakes causes the seabed to be displaced

2. A large volume of water is lifted forming waves of a great wavelength and low height of less than 1 meter

3. The waves travel towards land at high speeds around 800km/h

4. On approaching the coast, greater friction with the shallower seabed slows the waves down

5. The waves get closer together and increase in height. Waves can reach up to height of 15m or more, travel at a speed of 30 - 50 km/h and devastate shorelines that waves hit

6. Before a tsunami occurs the sea may recede from the shore because the sea water fills in the void caused by displacement of the seabed

Tsunami examples

1. 2004 Indian Ocean Tsunami

   • Triggered by a 9.1Mw undersea earthquake near Sumatra Indonesia

   • Tsunami waves slammed into the coasts of 11 Indian Ocean countries from Indonesia to Somalia in Africa

   • More than 230000 people were killed and entire coastlines and habits were destroyed

2. 2011 Tohoku Japan earthquake (Mw 9.0)

   • Triggered a tsunami up to 40m in height

   • Waves destroyed homes and infrastructure

   • Tsunami waves carried debris inland flooding and polluting large areas of land

   • Coastal city of Sendai suffered extensive damage and half its population was killed

   • In Iwate , 70000 pine trees were knocked down resulting in forest and biodiversity loss

   • The tsunami hit the pacific islands devastating the ecosystems

   • Entire bird nesting sites were lost and more than 100000 Layson Albatross Chicks were killed , and thousand of fish were washed ashore where they suffocated

Tephra examples (all pieces of all fragments of rock ejected into the air by an erupting volcano)

1. 1991 Mount Pinatubo eruption in the Philippines

   • Emitted huge amounts of ash

   • Buried more than 180km² of forests in ash of about 25cm

   • Destroyed 800km² of rice fields , affecting livelihoods of many farmers

   • Seven airports in the Philippines had to be closed and many flights were cancelled disrupting transport

   • Some planes were also damaged

Volcanic gases examples

1. Dieng volcano eruption in Indonesia in 1979

   • Released deadly amounts of carbon dioxide and killed about 150 people

   • Acid rain damages infrastructure (extra)

Lava flows examples

1. 2018 Kilauea eruption in Hawaii

   • Far-reaching lava flows destroyed more than 600 homes

   • Destroyed huge areas of forests and ecosystems

   • Telephone and power lines were damaged causing widespread communication outages

Pyroclastic Flows examples (A hot cloud of gas ash and rocks travelling down the slopes of a volcano at great speeds)

1. 2010 Merapi eruption in Indonesia

   • Blasted a series of pyroclastic flows down the slopes of the volcano which were inhabited by many villagers

   • About 350 people were killed, mostly due to burns and blast injuries

   • Huge areas of forest were burnt

Lahars examples (Mudflows comprising water and volcanic ash)

1. 1985 Nevado Del Ruiz eruption in Colombia

   • Released huge amounts of ash and volcanic rocks which melted snow and ice

   • The meltwater mixed with ash and rocks to form lahars

   • Fast-moving lahars buried more than 20000 people in the nearby town of Armero within second

   • Rivers were highly muddied by the lahars killing many fish

Volcanic Landslides examples

1. 1980 Mt St Helens eruption in USA

   • North face of the volcanic cone collapsed

   • Caused volcanic landslides that travelled as far as 23km from the volcano

   • Destroyed huge areas of land and killed many wildlife

The benefits of volcanic eruptions and living near volcanoes

1. Farming with fertile soil

   • Volcanic rocks form fertile soil

   • Produce higher crop yield

   • Example : Bali , Mount Agung , Mount Sinabung (2010 last eruption)

2. Extracting precious minerals and fossil fuels

   • Some magma may cool and solidify beneath volcanoes , forming precious minerals such as copper silver and gold

   • Examples : Mount Merapi

3. Harnessing geothermal energy

   • Derived from heat in the Earths crust

   • Cheaper electricity

   • Geothermal power plants

   • Examples : Iceland, electricity generated from geothermal power

     • Northern California , the Geysers geothermal field

4. Tourism activities

   • Hawaiian islands

Examples for DRM

Taipei 101 has a weighted damper near the top of the building to balance out ground shaking from earthquakes, This reduces the sway of the building during an earthquake and therefore the threat of the building collapsing

1. 2004 Indian Ocean tsunami caused an increased in the poverty line in Aceh, Indonesia

2. Importance of DR → the Mw 7.0 Haiti (Port-Au Prince) earthquake in 2010 had over 220000

   • On soft soil

   • Poor quality materials

   • epicentre was 25km west of the city

   • Unable to oragnise itself for disasters due to lack of education of what to do during a disasters

   • No community healthcare workers

   • Poor law enforceme

3. While the Mw 9.0 Tohoku Japan in 2011 had only about 19000.(6mins) (Earthquake resistant buildings)

   • Warning systems detected strong tremors and stopped bullets trains saving passengers (EEW)

   • 3000 students survived thanks to city disaster prevention education programmes

   • By 2016 majority were rehoused

4. the Mw 8.8 Chile earthquake 2010 had only 500 casualties

5. Time of shaking → 1995 Kobe Japan earthquake (Mw 6.9) occurred at 6am more than 6000 lives lost

6. 2018 Eruption of Kilauea in Hawaii

   • 24 injuries

   • 600 homes destroyed

   • USD$800 million in property damage

7. 2010 Eruption of Mount Merapi in Indonesia

   • Volcanic bombs spread over a distance of 10km

   • 350000 people evacuated

   • About 350 people were killed

8. 1991 Mount Pinatubo Philippines

   • Ashfall and tephra due to heavy rain

   • 100000 homes destroyed

   • 90000 hectares of damaged farmland

9. After the 1933 tsunami in Japan (land use planning was implemented, things shifted to higher ground)