HAZARDS DUE TO NATURAL DISASTERS DISASTER MANAGEMENT HAZARDS DUE TO NATURAL DISASTERS

TSUNAMI FAULT RUPTURE TECTONIC DEFORMATION DAMAGE/LOSS FOUNDATION FAILURE EARTHQUAKE DAMAGE/ LOSS SITE AMPLIFICATION DAMAGE/ LOSS GROUND SHAKING LIQUEFACTION DAMAGE/ LOSS DAMAGE/LOSS LANDSLIDES DAMAGE/ LOSS AFTERSHOCKS DAMAGE/ LOSS SEICHE DAMAGE/ LOSS

TECTONIC PLATES

Fault: A fault is a break in the earth's crust along which movement can take place causing an earthquake Tsunami are waves caused by sudden movement of the ocean due to earthquakes, landslides on the sea floor, land slumping into the ocean, large volcanic eruptions or meteorite impact in the ocean

TSUNAMI HAZARDS TSUNAMI WAVE RUNUP Tsunami runup occurs when a peak in the tsunami wave travels from the near-shore region onto shore. Runup is a measurement of the height of the water onshore observed above a reference sea level COASTAL EROSION

A TSUNAMI WAVE CAN REACH 10 M OR MORE IN HEIGHT

Tsunamis Are Associated with Subduction Zone Earthquakes M 7 or larger earthquakes that occur in oceanic subduction zones can cause: Tsunamis

HIGH VELOCITY IMPACT OF INCOMING WAVES CAUSES OF DAMAGE HIGH VELOCITY IMPACT OF INCOMING WAVES INLAND DISTANCE OF WAVE RUNUP VERTICAL HEIGHT OF WAVE RUNUP TSUNAMIS INADEQUATE RESISTANCE OF BUILDINGS FLOODING INADEQUATE HORIZONTAL AND VERTICAL EVACUATION PROXIMITY TO SOURCE OF TSUNAMI

VOLCANO

Definition A mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapour, and gas are have been erupted from the earth's crust. vent cone conduit magma chamber

Volcanic Hazards Pyroclastic flow: Perhaps the biggest hazards are pyroclastic flows. These are hot, fast moving, high particles concentration flows of gas, rock and ash.

The direct force of a pyroclastic flow traveling at 10’s of metres per second and carrying boulders as large as houses is extremely damaging. Pyroclastic flows have temperatures commonly in excess of 400 degrees Celsius. Hot enough to burn forests and wooden structures.

Lahars/Mud flows: ‘Lahar’ is an Indonesian term that describes a hot or cold mixture of water and rock fragments flowing down the slopes of a volcano and (or) river valleys. Hot volcanic activity can melt snow and ice Melt water picks up rock and debris Forms fast flowing, high energy torrents Destroys all in its path

Pyroclastic fall: An explosive eruption will produce an eruption column of hot gas, ash and debris ejected kilometres into the air. As this debris falls back down to the ground it can cause a lot of damage Ash load Collapses roofs Brings down power lines Kills plants Contaminates water supplies Respiratory hazard for humans and animals

Lava flow Lava flows although generally slower moving and less catastrophic than pyroclastic flows still remain dangerous. Lava flows have temperatures in excess of 200 degrees Celsius. Therefore will burn any flammable material it contacts with. Thick lava flows will bury all in it’s path including infrastructure (buildings, roads, waterways etc.) and agricultural land.

It is not just explosive volcanic activity that can be hazardous It is not just explosive volcanic activity that can be hazardous. Effusive (lava) activity is also dangerous.

Noxious Gas Magma contains dissolved gases that are released into the atmosphere during eruptions. Gases are also released from magma that either remains below ground (for example, as an intrusion) or is rising toward the surface. In such cases, gases may escape continuously into the atmosphere from the soil, volcanic vents, fumaroles

Effects: Lead to volcanic air pollution. The liquid drops of sulfuric acid promote the destruction of the Earth's ozone layer.