Geologic Hazards

Earthquakes - Learn about earthquakes and how they have affected cities and people.

Geology Dictionary - contains thousands of geological terms with their definitions.

Storm Surge can be the most damaging and deadly aspect of a hurricane.

Landslides A USGS fact sheet about landslides and events that trigger them.

Largest Hurricanes Are they determined by wind speed, value of damage, most deaths?

Volcanoes Articles about volcanoes, volcanic hazards and eruptions past and present.

Liquefaction occurs when water-saturated soil is severely shaken and loses strength.

Abandoned Mines accidents take 20 to 30 lives per year. Many could be prevented.

Expansive Soil Causes more damage than floods, hurricanes & tornadoes combined.

Hurricane Names How are hurricanes named? Is your name on the list?

Most Powerful Eruption of the 20th Century - and most people have never heard of it.

What Causes a Tsunami? Learn how plate motions trigger earthquakes and tsunamis.

Homeowners Insurance and Geologic Hazards Most policies do not cover geologic hazards.

Volcanic Explosivity Rating volcanic eruptions based upon the volume of tephra ejected.

World Record Lightning - This lake has more lightning than any other place in the world.

Yosemite Rock Fall Photos A photo sequence of a rockfall and debris avalanche by Herb Dunn.

Lightning Strikes Map - shows the worldwide distribution of lightning activity.

Geology Tools - Hammers, field bags, hand lenses, maps, hardness picks, gold pans.

Atlantic Tsunamis Rare events that can cause damage and threaten millions of people.

Largest Tsunami - The wave with the highest run-up was in Lituya Bay, Alaska.

Indian Ocean Tsunamis Deadly tsunamis triggered by earthquakes and volcanoes.

Yosemite Rockfall Hazards have been mapped by the National Park Service.

Pacific Tsunamis This ocean is surrounded by plate boundaries, that can produce tsunami.