Tectonics Flashcards
What percent of earthquakes are found along there ring of fire?
70%
What are found at divergent margins, convergent margins and conservative margins
Volcanoes and earthquakes
Volcanoes and earthquakes
Earthquakes
What is oceanic crust and continental crust?
Oceanic = younger, thinner but heavier(responsible for subduction)
Continental = older, thicker,lighter/less dense
Tectonic theory order?
- Francis bacon (west coast of Africa and east coast of South America looked liked they fit, supercontinent/jigsaw theory)
- Alfred Wegener (pangea,geological,climatological and biological/fossil evidence)
- Maurice Ewing (mid Atlantic ridge and Paleomagnetism)
- Harry Hess (seafloor spreading, volcanoes erupted/lava flowed out and formed seabed,proven by sonar)
Conservative example
SAN Andrea’s fault: North America and Pacific plate prone to earhtqaukes
Transform faults
Convergent example
Destructive ( continental and oceanic) and collision (continental and continental)
The Andes (O+C): Nazca forced under South American plate but friction prevents subduction.
Himalayas (C+C): Indian and Eurasian plate collide leading to fold mountains.
Oceanic trenches,fold mountains and island arcs.
Divergent example
Mid Atlantic ridge: North American and Eurasian plates, moving away from each other > rift valleys and volcanoes.
Mid ocean ridges and rift valleys.
Name all the hazard models
- Disaster risk and age index
- Pressure and release model(PAR) = disaster is the intersection of progression of vulnerability and risk [root causes,dynamic pressures and unsafe conditions]
- Hazard profile: (shows main characteristics)
4.Disaster and vulnerability (Deggs model):
Disaster only occurs when hazardous event crosses over with vulnerable population/interacts)
- Risk-Poverty nexus: how poverty affects risk
- Swiss cheese model: holes=weakness in lines of defence >align>disaster
- Risk disk : tries to explain reason for decline in deaths in terms of mitigation,preparedness etc.
- Hazard management cycle: where government and other orgs. Work together to protect people e.g. prevention and mitigation > preparation > response > recovery.
- Park model: hazard response curve (relief,rehabilitation and reconstruction)
Types of disaster origins
Geophysical
Meteorological(short term/weath)
Hydrological
Climatological(long term)
Hazard adaption strategies
High tech monitoring
Crisis mapping
Public education
Modelling hazard impact
Hazard mitigation strategies
Land use zoning
Diverting lava flows
Hazard resistant design and engineering defences
GIS mapping
CASE STUDY: Haiti earthquake 2010 developing
Cause: strike slip fault (conservative) between NA and Caribbean plates, subduction then pinged back up > earthquake and tsunami
15 MILES FROM PORT AU PRINCE, shallow focus.
Effects: 200,000 DEAD, levelled city, travelling west/repeating , ORIGINAL SHOCK LASTED 1 MINUTE , port destroyed (aid), Haiti sits on soft soil,houses built on hard rock nearer to fault survived (amplification), 1 IN 3 BUILDINGS COLLAPSED/50% DESTROYED, little steel reinforcement, pop growth > no reg, poorest country in western hem, coral reef uplifted > displaced water and tsunami KILLED 7 PEOPLE
CASE STUDY: Tohoku tsunami + earthquake, 2011, developed
Off Pacific coast, hypocentre below 6KM OF WATER, 100KM OFF COAST OF JAPAN.
Causes: Pacific plate subduct underneath Eurasian plate, stress built up over 100 YEARS, MAGNITUDE 9.1, SHOCKWAVES LASTED 5 MINUTES, 2 MILLION ATOMIC BOMBS, 6KM OF WATER > Tsunami, 500 AFTERSHOCKS.
Prep: 60 second warning,invested billions into quake proof building and early warning systems,Miyako: had training and sirens but sea wall failed. Fukushima: Power plant automatically shuts down.
Effects: 20,000 DEAD , 300,000 REFUGEES CREATED, 450,000 IN E SHELTERS, 122 BILLION IN TOTAL RECOVERY COSTS, farmland and fishing industry damaged, loss of housing, Airport destroyed, parts of coast dropped,liquefaction,wildfires.
Response: Power plant shut down, evacuation and shelters, Japanese self defence force deployed to find survivors and mark bodies, 110 COUNTRIES OFFERED AID.
CASE STUDY: Boxing Day Tsunami, 2004, Indian Ocean
Cause: Earthquake triggered tsunami (9.2), as a fault ruptured beneath Indian Ocean forcing Indian plate to thrust upward under Burma plate > displacement of water > tsunami.
10 M WAVES, 800KM/H WAVES.
Effects: 13 COUNTRIES AFFECTED, 230,000 DEAD, OVER 500,000 INJURED, 5 MILLION HOMES LOST, 7.5 BILLION IN AID/RECONSTRUCTION, Indonesia worst affected but last to receive aid (130,000 DEAD).
DART: deep ocean assessment and reporting of Tsunamis using surface buoys to report temp and pressure, could have reduced impacts.
