The Handy Geography Answer Book. Paul A Tucci

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      What does an earthquake feel like?

      Smaller earthquakes or tremors feel disorienting at first. You feel a sense that the room is spinning, as if you are becoming dizzy. Usually preceding an earthquake, when the initial tremors hit, you can hear the sounds of things rattling that you have never heard before, like glasses rubbing against each other and windows vibrating. With larger earthquakes, as the earth nearby tears or opens, you can hear a very loud rumbling sound that is similar to a passing train.

      How many mini-earthquakes happen each year on our planet?

      Experts at the U.S. Geological Survey believe that if we consider earthquakes of low magnitudes of between 2 and 2.9, there are an estimated 1.3 million mini-earthquakes each year, somewhere on Earth.

      How many really big earthquakes occur each year?

      On average, there are about 134 earthquakes of a magnitude 6.0–6.9, about fifteen of a magnitude 7.0–7.9, and one huge magnitude 8.0–8.9 earthquake each year. Many of these really big earthquakes occur in the ocean, so we don’t hear much about them.

      Is a magnitude ten the top of the Richter scale?

      While the media often refers to the Richter scale as being on a scale of one to ten, there is no upper limit, even though the strongest quakes are not as high as ten.

TSUNAMIS

      What causes a tsunami?

      A tsunami, also known as a seismic sea wave, is usually caused by an earthquake that occurs under the ocean or near the coast of a landmass. The seismic energy creates a large sea wave that can cause heavy damage hundreds or even thousands of miles from its source. The state of Hawaii is frequently struck by tsunamis.

      How does Hawaii protect itself from tsunamis?

      There is a sophisticated global monitoring network that provides warnings about possible tsunamis, allowing the islands of Hawaii and other coastal areas to prepare for impending disaster. Hawaii also has a thorough evacuation system to protect lives in the face of tsunami danger.

      What caused the great Indian Ocean tsunami of December 2004?

      The great Indian Ocean tsunami of December 2004 was caused by a magnitude 9.0 earthquake in the ocean off the coast of Sumatra, Indonesia, which then caused a reverberating swell of water to move toward the countries of Indonesia, Thailand, Sri Lanka, India, and the Maldives. Its effects were felt as far away as Africa before its energy finally dissipated.

      What was the effect of the 2011 Tohoku earthquake and tsunami that occurred in Japan?

      The magnitude 9.0 earthquake that occurred off the coast of Japan in March 2011 caused a tsunami, which melted down three nuclear reactors at the Fukushima Daiichi Nuclear Power Plant. Approximately 16,000 people lost their lives, and many millions of people were without electricity and water for several weeks after the incident.

      What is the Pacific Tsunami Warning Center?

      The United States has two tsunami warning centers that are administered by the National Oceanic and Atmospheric Administration: the Pacific Tsunami Warning Center based in Hawaii and the West Coast and Alaska Tsunami Warning Center. The Pacific Tsunami Warning Center is the command center for monitoring and warning all nations that may be affected by a tsunami. With data from a network of thirty-nine detection buoys called the DART array, the center can issue alerts of real-time earthquake activity in the Pacific basin and the tsunamis that may result, giving residents affected time to head to safe ground, away from low-lying coastal areas.

      What is the DART array?

      DART stands for the Deep-Ocean Assessment and Reporting of Tsunamis, which consists of an array of thirty-nine buoys that float in critical spots in the Pacific. Each DART system consists of an anchored seafloor bottom-pressure recorder (BPR) and a companion moored surface buoy for real-time communications. An acoustic link transmits data from the BPR on the seafloor to the surface buoy. The BPR collects temperature and pressure at fifteen-second intervals. In normal mode, it transmits the data every fifteen minutes. If there is an event, the system reports back data collected in fifteen-second intervals every minute.

      The Deep-Ocean Assessment and Reporting of Tsunami (DART) array helps to warn people early of an approaching tsunami.

HURRICANES

      Why are hurricanes so destructive?

      It is the floods caused by hurricanes that are the most destructive element. The low-pressure center of a hurricane causes a mound of water to rise above the surrounding water. This hill of water is pushed by the hurricane’s fierce winds and low pressure onto the land, where it floods coastal communities, causing significant damage. Hurricanes also spark tornadoes that contribute to the devastation.

      How fast do hurricane winds blow?

      The strongest hurricanes, or category 5 hurricanes, often have winds that reach speeds well over 150 miles (240 km) per hour.

      How are hurricanes ranked?

      We use the Saffir-Simpson Hurricane Wind Scale to rank the intensity and destructive capacity of hurricanes. Hurricanes are ranked on a scale of one to five, with category one hurricanes being the weakest and category five being the strongest and most destructive. The rankings for damage caused by each category of hurricane are: 1, minimal; 2, moderate; 3, extensive; 4, extreme (such as Hurricane Andrew in 1992); and 5, catastrophic.

      What was Hurricane Katrina?

      Hurricane Katrina was the name given to the hurricane that developed in the Gulf of Mexico and struck New Orleans and many other cities along the southern coast of the United States in late August 2005. Winds from Katrina were initially only a category two hurricane, with a tidal surge ranked as a category three.

FLOODS

      How many people died as a result of the subsequent failure of the levees and flooding after Hurricane Katrina struck?

      Approximately 1,460 people lost their lives following the landfall of Hurricane Katrina.

       Was the 2005 New Orleans disaster caused by a flood or a hurricane?

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