Earthquakes are notorious perils in California, but do you know how much damage they can do in the eastern U.S.? Our country turns out to vulnerable to many risky natural events: quakes and hurricanes, but also huge sinkholes and dust storms as well as rising seas, flooding rivers and wildfires. They cost lives and money. Identifying hazards like these and telling people how much risk the events pose at any given time is a focus of the U.S. Geological Survey, which partnered with Scientific American to create this 10-item quiz about our potential for different disasters. See how much you really know about our country’s dangers.

1. How many Americans live and work in areas exposed to potentially damaging earthquakes?

  1. About 10 percent of the population
  2. About 25 percent
  3. About 50 percent
  4. Almost all
Damage from the January 1994 earthquake in Northridge, Calif. Credit: USGS

ANSWER: C—Nearly 50 percent of the U.S. population live and work in areas of the 48 contiguous states, as well as earthquake-prone areas of Alaska, Hawaii and the U.S. territories, that are exposed to potentially damaging ground shaking from earthquakes. Looking only at the most severe ground-shaking levels, the 10 states with the most people at risk are, in descending order: California, Washington, Utah, Tennessee, Oregon, South Carolina, Nevada, Arkansas, Missouri and Illinois. Although this level of shaking is estimated to occur relatively infrequently, it could cause significant damage and causalities.

A Scientific American report explains the causes of tremors and what makes them stop, whether they can be predicted and whether our buildings can be made more quake-proof. In the middle of the country scientists are increasingly sure that wastewater injection tied to fracking for oil and gas is causing more tremors. To learn even more about earthquakes, look at

2. On average, how much are landslides estimated to cost the nation each year?

  1. $38 million
  2. $3.5 billion
  3. $1 billion
A rockslide has closed State Road 140 near Ferguson, Calif., since 2006. Credit: USGS

Answer: B—In the U.S. landslides cost the nation an estimated $3.5 billion per year. This is an estimate because there is no uniform method to track landslide losses or a central government agency that does so. Local losses can be very high. For example, the winter season rains associated with the 1997–98 El Niño caused landslide damage estimated at $210.2 million in the San Francisco Bay Area. Right now the USGS and the National Oceanic and Atmospheric Administration are working on a Debris-Flow Warning System to help provide forecasts and alerts.

Other countries also worry about slides: In Nepal researchers are putting sensors on mountains to forecast rockfall hazards. Learn more about the dangers in the U.S. at

3. How many potentially active volcanoes are there in the U.S.?

  1. 5
  2. 23
  3. 169
An explosion at Kilauea volcano in Hawaii on July 16, 2008. Credit: USGS

Answer: C—The U.S. is home to 169 active volcanoes, many of which could erupt at any time. The Volcano Hazards Program, run by the geological survey, monitors activity around these volcanoes—earthquakes, ground movement, volcanic gas, rock chemistry, water chemistry, remote satellite analysis—on a continuous or near–real-time basis. Monitoring lets the agency issues warnings and alerts, including imminent or ongoing eruptions, ash fall forecasts and notifications when eruptions have ended.

Scientists are also examining dormant volcanoes such as the behemoth below Yellowstone National Park. Worldwide, Indonesia is most at risk from eruptions, according to researchers. Learn more about volcano prediction at

4. How much of the U.S. is vulnerable to sinkholes, which are rock areas that dissolve easily?

  1. 100 percent
  2. 55 percent
  3. 5 percent
  4. 20 percent
Sinkholes damaged homes in western Florida in 2010. Credit: USGS

Answer: D—About 20 percent of the nation sits atop of terrain known as karst. In these areas the underlying rock can be dissolved by groundwater, and then the ground is vulnerable to collapse. Sinkholes are common in these places and can be as sudden as they are devastating. The most damage from sinkholes tends to occur in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania. Many sinkholes also form after human activity. Collapses can occur above old mines, from leaky faucets, when sewers give way or due to groundwater pumping and construction.

Read more about the hazards of karst and also how Florida has been trying to map home-engulfing sinkholes. And learn more about dissolving ground at

5. How many people in U.S. have floods killed each year, on average, over the past 30 years?

  1. 8
  2. 82
  3. 332
In June 2011 downtown Minot, N.D., was inundated by the Souris River. Credit: USGS

Answer: B—Floods have killed an average of 82 people each year during the last 30 years, and caused $8 billion in damages annually. Floodwatch, a Web site operated by the USGS, offers a map with hourly updates of flood conditions at over 3,000 locations throughout the U.S.

There are also giant flows of vapor, dubbed “atmospheric rivers,” that unleash floods periodically, and climate change could increase their frequency. To understand more about traditional floods, look at

6. In what year did wildfires burn the most acreage in the U.S.?

  1. 1984
  2. 1991
  3. 2015
A wildfire burning in Alaska in April 2016. Credit: USGS

Answer: C—The 10 million acres that burned in the U.S. in 2015 were the most on record, primarily due to drought conditions. The national average has been 6.7 million acres for the past 10 years, and 3.6 million acres burned in 2014. Wildfire risks to firefighters, homes and property, along with threats to communities, landscapes and species are increasing, as are response and recovery costs. Alaska was of particular concern last year; over five million acres were blackened by intense wildfires.

Worldwide, forests from the Arctic to Indonesia are flaring up more often as climate changes. In the U.S. the geological survey plays a major role in mapping areas of wildfire hazards, and you can find out about it at

7. What months typically make up hurricane season along the Atlantic Coast?

  1. June–November
  2. March–August
  3. May–October
Hurricane Irene destroyed a long stretch of road in Rodanthe, N.C., in late August 2011. Credit: USGS

Answer: A—From June through November major tropical cyclones generate the most concern. On average during this period, 12 tropical storms, six of which become hurricanes (categorized as having winds exceeding 74 miles per hour), form over the Atlantic Ocean, Caribbean Sea or Gulf of Mexico, according to the National Weather Service. In addition to high winds, heavy rainfall and storm surges cause tremendous damage.

Researchers have explored hurricane origins to find out what makes the storms so big. Learn more about storm seasons at

8. Are sea level rise rates increasing faster along the U.S. west or east coast?

  1. West
  2. East
  3. It's the same for both
The marshes of the Plum Island Estuary in Massachusetts are disappearing beneath the Atlantic. Credit: USGS

Answer: B—Along portions of the Atlantic coast, rates of sea level rise are increasing three to four times faster than globally. Since about 1990 sea level rise in the 600-mile stretch of coastal zone from Cape Hatteras, N.C., to north of Boston has increased from two to 3.7 millimeters per year. Globally, annual sea level rose less, going up from 0.6 to 1.0 millimeter.

Earlier this year scientists reported that sea levels were going up faster now that at any time during the past 2,000 years. Learn about the rising tides at

9. True or false? The same size earthquake will cause damage over a larger area in the western U.S. than the east.

  1. True
  2. False
A magnitude 5.8 quake hit this house in Virginia on August 23, 2011. Credit: USGS

Answer: B—Earthquake shaking in the eastern U.S. can travel much farther and cause damage over larger areas. The difference is due in part to the geologic structure and rock properties that allow seismic waves to travel farther without weakening. Whereas earthquakes occur more frequently in the west, people in the east should still be prepared. A geologist explained in Scientific American why eastern quakes travel so well, and the geological survey also has information at

10. In the near future, which part of the U.S. is likely to see large increases in dust storms?

  1. Southwest
  2. Midwest
  3. Southeast
Dust storm near Winslow, Ariz., in April 2011. Credit: USGS

Answer: A—Dust storm frequency has increased and is projected to continue in the Southwest, affecting human and ecosystem health. Several lines of evidence link these storms to more intensive land-use practices and a decadelong drought. Climate model projections of sustained drier conditions in the Southwest will likely reduce the amount of perennial vegetation covering the land, and a growing human population can disturb naturally protected soil surfaces. Both of these factors make it more likely that soils will be eroded in high winds and increase the amount of particulate matter in the air we breathe.

Read about connections between droughts and last century’s “Dust Bowl” and how the situation is repeating. Learn even more about dry soil and high winds at

This quiz was developed from materials provided by the U.S. Geological Survey (USGS). The survey is dedicated to learning from past events and progressing forward with innovative research and technology to help build more robust and safer communities. Learn more about the survey’s research as well as preparation strategies at its natural hazards Web site.