HIGHLIGHTS OF NOTABLE DISASTERS OF 2012 PART 6: LANDSLIDES More lectures at Disasters Supercourse - http://www.pitt.edu/~super1/collections/collection52.htm Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA 

2012 WAS NOT A YEAR FOR MANY NOTABLE LANDSLIDES Most of 2012’s named tropical storms, hurricanes, and typhoons died without making landfall; hence, there were fewer storm-generated landslides than in many previous years.

2012 ATLANTIC BASIN STORM TRACKS AS OF DEC. 1

22 STORM TRACKS AS OF OCTOBER 21, 2012

2012 WAS NOT A YEAR FOR MANY NOTABLE LANDSLIDES 2012 did not have as many damaging earthquakes as usual; hence, there were fewer earthquake-generated landslides than in previous years.

BACKGROUND

LANDSLIDES represent permanent deformation caused by the downward and outward movements of large volumes of soil and/or rock down- slope under the influence of the force of gravity.

PHYSICS OF LANDSLIDES Landslides occur naturally. Landslides can be triggered and/or exacerbated by: 1) Water (from precipitation during a tropical storm, hurricane, or typhoon), or 2) Vibrations (from ground shaking during an earthquake.

PHYSICS OF LANDSLIDES These phenomena either reduce the friction or increase the down-slope force.

SITING AND BUILDING ON UNSTABLE SLOPES CAUSES OF DAMAGE SITING AND BUILDING ON UNSTABLE SLOPES SOIL AND ROCK SUCEPTIBLE TO FALLS SOIL AND ROCK SUCEPTIBLE TO TOPPLES LANDSLIDES SOIL AND ROCK SUCEPTIBLE TO SPREADS SOIL AND ROCK SUSCEPTIBLE TO FLOWS CASE HISTORIES PRECIPITATION THAT TRIGGERS SLOPE FAILURE SHAKING GROUND SHAKING THAT TRIGGERS SLOPE FAILURE

ELEMENTS OF LANDSLIDE RISK HAZARDS EXPOSURE RISK VULNERABILITY LOCATION

LOCATIONS WITH STEEP UNSTABLE SLOPES (E. G LOCATIONS WITH STEEP UNSTABLE SLOPES (E.G., IN MOUNTAINOUS AREAS) TEND TO HAVE THE MOST FREQUENT AND DEADLY LANDSLIDES

CHINA: NEPAL-TIBET ROAD

CHINA

INDIA

WORST LANDSLIDE: 1970 IN PERU A M7.7 earthquake that occurred offshore Peru in 1970 triggered a massive landslide of snow and rock in the Nevados Huascaran Mountains.

WORST LANDSLIDE: (CONTINUED) 100 million cubic km of rock and soil buried Yungay, Ramrahirca, and several villages, killing 18,000.

IMPACTS IN THE USA Landslides occur in all 50 states and U.S. territories, On average, they cause $1-2 billion in damages and more than 25 fatalities each year

USA (CALIFORNIA)

USA

LANDSLIDES IN LOCATIONS WITH UNSTABLE SLOPES AND DIVERSE AND WIDE-SPREAD INFRASTRUCTURE TEND TO BE COSTLY