Natural Hazard Impact Factors Natural events can cause great loss of life or property damage: Natural events can cause great loss of life or property damage: 2004: Asian Tsunami: >200, : Asian Tsunami: >200, : Bangladesh Cyclone: 300, : Bangladesh Cyclone: 300, : China earthquake: 300, : China earthquake: 300,000 Different types of Natural Hazards: Different types of Natural Hazards: Volcanism, earthquakes, Hurricane, tornado, Tsunami, Flooding, Landslides Volcanism, earthquakes, Hurricane, tornado, Tsunami, Flooding, Landslides Impact of a disaster is related to magnitude (how big) and frequency (how often). Actual damage depends on other factors too, such as population, land-use, local geology etc. Impact of a disaster is related to magnitude (how big) and frequency (how often). Actual damage depends on other factors too, such as population, land-use, local geology etc. Catastrophe: immense damage: recovery and rehabilitation is a long process – New Orleans still not recovered after now 10 years Catastrophe: immense damage: recovery and rehabilitation is a long process – New Orleans still not recovered after now 10 years

Damages from Natural Hazards in US

Evaluating Hazards  Fundamental Principles:  Hazards are repetitive and predictable  Risk Analysis is important for understanding impact  Hazards are linked, e.g., volcano, earthquake, tsunami, landslide, flooding, forest fire..  Human interference can magnifying damage  Consequences can be minimized for some types of hazards but not others.

Disaster Prediction Location:  e.g., Volcanoes and earthquakes along plate boundaries Probability of occurrence  Hazards are statistical  With sufficient data probability of occurrence can be calculated Precursor events  Volcanoes, earthquakes, landslide, flooding, often associated with precursor events Forecasting  Is possible by monitoring hazards e.g., hurricanes, tsunamis, volcanic eruption etc Warning  Should be issued even at the risk of the hazard not materializing. However, the public doesn’t understand this.

Risk Assessment Risk Determination  Risk= probability X damage Acceptable Risk  Risk-tolerance level of the society  Can vary: High for automobiles but low for nuclear accident Problem and opportunities  Lack of long term data– how do we calculate risk?  Information may be complex and difficult to analyze e.g., what is the effect of radiation leak from a nuclear reactor?  Better risk assessment will lead to better decisions

Human Response to hazards Reactive – traditional response  Stages: Emergency: Search and Rescue, shelter, opening roads Restoration: water and power, return to home, cleaning of rubble Reconstruction I: Return to pre-disaster level Reconstruction II: improvement  Rapid Restoration can be counter-productive Anticipatory – a better way to reduce damage  Hazard perception by people and by government  Land-use planning: avoid hazardous locations  Insurance: often not extended to high risk areas  Evacuation plans and Disaster preparedness Artificial control  Difficult, expensive and often cause more harm Channelization of Kissimmee river Sea walls, dams…

. Global climate and hazards A. Global and regional climate change may significantly affect incidence of storms, landslides, drought, fires A. Global and regional climate change may significantly affect incidence of storms, landslides, drought, fires  a. sea level rise may increase coastal erosion  b. shift in food production areas  c. expansion of deserts and semi-deserts

Population increase, land-use change, and natural hazards A. Population increase and hazardous events A. Population increase and hazardous events –1. as population increases, need for planning to minimize losses from natural disasters also increases B. Land-use change and hazardous events B. Land-use change and hazardous events –1. past half-century has seen dramatic increase in great catastrophes –2. vast majority of natural disaster deaths between were in developing world  a. Hurricane Mitch: hillsides stripped because of heavy rains on cleared and burned land  b. Yangtze River: timber harvest and conversion to agriculture has increased flood hazard