Читать книгу The Handy Geography Answer Book - Paul A Tucci - Страница 15
ОглавлениеWhat is the difference between a watch and a warning?
The U.S. National Weather Service issues watches and warnings for a variety of hazards when they may be imminent. A watch (such as a tornado watch or a flood watch) means that such a hazardous event is likely to occur or is predicted to occur. A warning is more serious. It means that a hazard is already occurring or is imminent. Warnings are usually broadcast on television and radio stations via the Emergency Alert System (formerly known as the Emergency Broadcast System).
How should we prepare for disaster?
Disasters can and do happen everywhere. You should prepare for disaster by having a disaster supply kit with supplies for you and everyone in your family available at home and work, as well as a minikit in your automobile. It should include food, water, first-aid equipment, sturdy shoes, an AM/FM radio (with batteries kept outside of the radio), a flashlight (with batteries kept outside of the flashlight), vital medication (especially prescription medication), blankets, cash (if the power and computers are down, credit and ATM cards won’t work), games and toys for children, and any other essentials. Contact your local chapter of the Red Cross for more information about disaster preparedness.
Should we use candles after a disaster or power outage?
Many deaths and a great deal of property damage have been caused by fires resulting from people using candles following a disaster. People leave candles burning as a source of light, but these can fall over and start fires. It is strongly advised that people not use candles when the power goes out. There are many flashlights and battery-operated lanterns that are available commercially and should be part of your disaster supply kit. Most cell phones have flashlights as part of the rear-camera light, too.
What’s the difference between the old Emergency Broadcast System and the Emergency Alert System?
The Emergency Broadcast System (EBS), created in 1964 to warn the country of a national emergency such as nuclear attack, became the Emergency Alert Service (EAS) in 1997. The old EBS system relied on one primary radio station in each region to receive an emergency message and then broadcast it to the public and other media outlets. The new system, which also includes cable television, operates via computer and can be automatically and immediately broadcast to the public. It also allows additional local governmental agencies the opportunity to broadcast emergency messages. Future plans for the EAS include radios and televisions that will automatically turn on when an alert is announced.
What is the leading cause of disaster-related deaths in the United States?
Lightning is the leading cause of disaster-related deaths in America. From 1940 to 1981, about 7,700 people died from lightning strikes, 5,300 from tornadoes, 4,500 from floods, and 2,000 from hurricanes. So, it’s best to avoid open spaces, elevated groundwater, tall, metal objects, and metal fences during an electrical storm. In an analysis of eight years of data from 2006 to 2013 by experts at the National Weather Service of the NOAA, fishermen accounted for three times the number of deaths from lightning strikes than golfers. About 261 people were killed by lightning during this period, roughly three per year.
What is the best way to help after a disaster?
Disaster relief agencies such as the Red Cross are in vital need of money after a disaster to purchase necessary items for victims or provide financial support to them. Go online or call your local chapter of the Red Cross to find out how to help. Donating food or clothing is burdensome on the agencies in the immediate aftermath of a disaster, as personnel are not available to sort, clean, or distribute donated goods.
How did a map help stop the spread of cholera?
During an 1854 cholera outbreak in London, a physician named John Snow mapped the distribution of cholera deaths. His map showed that there was a high concentration of deaths in an area surrounding one specific water pump (water had to be hand-pumped and carried in buckets at the time). When the handle was taken off of the water pump, the number of cholera deaths plummeted. When it was determined that cholera could be spread through water, future epidemics were curbed. This was the beginning of medical geography.
What are incidence maps?
Researchers at such institutions as the Centers for Disease Control and Prevention (CDC) use incidence maps, which plot where and how people have been infected or exposed to such potentially harmful viruses as influenza, Ebola virus, West Nile virus, and HIV in order to understand the rate of transmission as related to geography. An incidence map may help scientists figure out the origin of a disease and where and how quickly it is spreading. Global incidence maps are of increasing importance in the fight against potentially harmful biological disasters.
How does medical geography help control the spread of diseases?
Medical geographers and epidemiologists (scientists who study diseases and epidemics) use mapping to monitor the spread of diseases and locate the source of a disease. For example, by mapping a group of inordinately high numbers of cancer patients in a city, we may find that all live close to a factory that has been releasing cancer-causing toxins into the groundwater. By identifying the source and spread of a disease, the disease can often be combated. Organizations like the Centers for Disease Control and Prevention use maps to describe the outbreak of such diseases as Ebola and to determine quarantine areas and where to focus treatment efforts.
Which natural disasters doesn’t southern California experience?
Urban southern California is plagued by many natural disasters, including earthquakes, wildfires, floods, landslides, and tornadoes. Thankfully, they rarely receive snowstorms or hurricanes.
What causes wildfires to occur?
Approximately 10% of all wildfires are caused by lightning that ignites material and forms a wildfire. Experts at the U.S. Park Service assert that the remaining 90% of all wildfires are started by human activity, like campfires, the burning of trash, discarded cigarettes, and arson.
How can I learn more about disasters in my town?
Each community should have its own disaster plan that includes a history of past disasters (those that have happened in the past are likely to occur in the future) along with plans for dealing with future disasters. You should be able to consult this plan to learn how your community would cope with disaster and to find out the locations of evacuation routes and shelters. Many communities place important disaster-planning information online for easy reference.
How are volcanoes formed?
Volcanoes are the result of magma rising or being pushed to the surface of the Earth. Hot liquid magma, which is located under the surface of the Earth, rises through cracks and weak sections of rock. The mountain surrounding a volcano is formed by lava (called magma until it arrives at the Earth’s surface) that cools and hardens, making the volcano taller, wider, or both.
What is the difference between magma and lava?
Magma is hot, liquefied rock that lies underneath the surface of the Earth. When magma erupts or flows from a volcano onto the Earth’s surface, it becomes lava. There is no difference in substance; only the name changes.
What is the Ring of Fire?
If you were to look at a map of the world’s major earthquakes and volcanoes, you would notice a pattern circling the Pacific Ocean. This dense accumulation of earthquakes and volcanoes is known as the Ring of Fire. The ring is due to plate tectonics and the merger of the Pacific Plate with other surrounding plates, which creates faults and seismic activity (especially Alaska, Japan, Oceania, and coastal North and South America), along with volcanic mountain ranges, such as the Cascades of the U.S. Pacific Northwest and the Andes of South America.
The Ring of Fire encircles the Pacific Ocean with volcanic and earthquake activity.
How many active volcanoes are there in the world?
There are about 1,500 potentially active volcanoes around the world, but the number often depends on how we define active. Experts at the National Geographic Society consider approximately 1,900 volcanoes on Earth to be active, with evidence of activity and a strong likelihood to explode again. Most are located in the Ring of Fire surrounding the Pacific Ocean. About one-tenth of the world’s active volcanoes are located in the United States. A volcano is considered active if it has erupted in the last 10,000 years. If you were to consider how many volcanoes may be at the bottom of the sea floor, there could be many thousands more.
What are some of the world’s most active volcanoes, in terms of numbers of years of eruptions?
The volcanoes that have been active the most number of years include Mt. Etna in Italy (3,500 years), Mt. Stromboli in Italy (2,000 years), and Mt. Yasur in Vanuatu (800 years).
How many active volcanoes are located in Europe?
There are more than sixty active volcanoes in Europe and more than forty dormant ones, many of which are located in Italy, Sicily, and Greece.
Which volcano poses the most risk to people in Europe?
Mt. Vesuvius, on the southwestern coast of Italy, lies very near a city of more than one million people: Naples. Although it last erupted in 79 C.E., it is still active, and geologists predict there is a very good chance it will erupt again, potentially putting the city of Naples and the surrounding area at risk.
How many active volcanoes does Iceland have?
Iceland, formed by volcanoes, lies between two tectonic plates along the Mid-Atlantic Ridge and is home to approximately 130 volcanoes. Of these, 30 are considered to be active.
Where are the active volcanoes in the United States?
Alaska, Washington, Oregon, and California have many potentially active volcanoes. The most recent large-scale eruption in the United States was that of Mt. St. Helens in southern Washington State in 1980. Other volcanoes in the region, such as Mt. Shasta, Mt. Lassen, Mt. Rainier, and Mt. Hood, could erupt with little warning.
What is so interesting about volcanoes in Alaska?
Alaska contains approximately 130 volcanoes, with 90 that have been active in the last 10,000 years. Volcanoes in the state of Alaska account for over 75% of all volcanoes that have erupted in the United States in the last two hundred years.
The ruins of Pompeii attract tourists today, but it is difficult to imagine the horror of an entire city wiped out by a volcano.
How was Pompeii destroyed?
In the year 79 C.E., the volcano Mt. Vesuvius erupted and buried the ancient Roman town of Pompeii under 20 feet (6 meters) of lava and ash. Pompeii is famous because excavations of the city, which began in 1748 and continue to this day, provide an excellent look at Roman life at the beginning of the millennium. The covering of the city by debris preserved not only the places where people last stood but also paintings, art, and many other artifacts. The nearby city of Herculaneum was also buried and perfectly preserved. Although a much smaller version of Pompeii, it contains some of the best art, architecture, and examples of daily life in Roman times and is only twenty minutes away from Pompeii. Even loaves of bread that were baking on the day of the eruption are preserved in a nearly 2,000-year-old bakery.
What creates earthquakes?
The tectonic plates of the Earth are always in motion. Plates that lie side by side may not move very easily with respect to one another; they “stick” together, and occasionally they slip. These slips (from a few inches to many feet) create earthquakes and can often be very destructive to human lives and structures.
What is an epicenter?
An epicenter is the point on the Earth’s surface that is directly above the hypocenter, or the point where earthquakes actually occur. Earthquakes do not usually occur at the surface of the Earth but at some depth below the surface.
What is a fault?
A fault is a fracture or a collection of fractures in the Earth’s surface where movement has occurred. Most faults are inactive, but some, like California’s San Andreas Fault, are quite active. Geologists have not discovered all of the Earth’s faults, and sometimes earthquakes occur that take the world by surprise, like the one that occurred in 1994 in Northridge, California. When earthquakes occur on faults that were previously unknown, they are called blind faults.
What is the significance of the infamous San Andreas Fault?
The infamous San Andreas Fault lies at the border between the North American and the Pacific tectonic plates. This fault is situated in California and is responsible for some of the major earthquakes that occur there. Los Angeles is on the Pacific Plate, but San Francisco is on the North American Plate. The Pacific Plate is sliding northward with respect to the North American Plate, and, as a result, Los Angeles gets about half an inch closer to San Francisco every year. In a few million years, the two cities will be neighbors.
Was San Francisco destroyed by earthquake or by fire in 1906?
In 1906, a very powerful earthquake struck San Francisco, California, which sparked a fire that destroyed much of the city. In an effort to preserve San Francisco’s image with residents and would-be visitors, official policy regarding the disaster stated that it was not the earthquake but mostly the fire that destroyed the city. Official books and publications produced after the earthquake referred to both the fire and the earthquake as having caused the damage. In fact, the earthquake did considerable damage to the city and killed hundreds.
Will California eventually fall into the ocean?
No, it will not. The famous San Andreas Fault, which runs along the western edge of California from the San Francisco Bay area to southern California, is known as a transverse fault. This means that the western side of the fault, which includes places like Monterey, Santa Barbara, and Los Angeles, is sliding northward with respect to the rest of the state. In a few million years, the state’s two largest urban areas, San Francisco and Los Angeles, will be right next to each other. The fault is moving at about two centimeters (just under an inch) a year.
A view of San Francisco taken from the Union Ferry Building and looking toward Market street shortly after the 1906 earthquake and fire.
Which states are earthquake-free?
While a twenty-year period isn’t an excellent indicator, there are four states that had no earthquakes between 1975 and 1995: Florida, Iowa, North Dakota, and Wisconsin.
Is there a high risk of earthquakes in the Midwestern United States?
Great earthquakes struck the New Madrid, Missouri, area in 1811 and 1812. They caused considerable damage (some areas experienced shaking at the level of XI on the Mercalli scale) and were felt as far away as the East Coast. The potential exists for future earthquakes in the region, since earthquakes have occurred there before. Planning and preparedness continues throughout the region, centered at the junction of Missouri, Arkansas, Illinois, Kentucky, Tennessee, and Mississippi.
What should I do in the event of an earthquake?
Duck, cover, and hold! Duck under a table, counter, or any area that can provide protection from falling objects. Cover the back of your head with your hands to help protect against flying debris. Hold on to the leg of the table or anything solid to ride out the shaking.
Is it safe to stand in a doorway during an earthquake?
While a doorway is a nice, structurally sound place to be during an earthquake, officials have found that many people are injured when a door swings open and closed during an earthquake, so you may want to avoid standing in a place where your fingers can become crushed.
What is the Richter scale?
The Richter scale measures the energy released by an earthquake. It was developed in 1935 by California seismologist Charles F. Richter. With each increase in Richter magnitude, there is an increase of thirty times the energy released by an earthquake. For example, a 7.0 earthquake has thirty times the power of a 6.0 earthquake. Each earthquake only has one Richter magnitude. The strongest earthquakes are in the 8.0–9.0 range—8.6 for Alaska’s 1964 earthquake and 8.0 for China’s 1976 earthquake in Tangshan.
What is the Mercalli scale?
The Mercalli scale measures the power of an earthquake as felt by humans and structures. Italian geologist Giuseppe Mercalli developed it in 1902. The Mercalli scale is written in Roman numerals, and it ranges from I (barely felt) to XII (catastrophic). The Mercalli scale can be mapped surrounding an epicenter and will vary based on the geology of an area.
The Mercalli Scale of Earthquake Intensity
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.
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.
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.
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?
The initial cause of the disaster was Hurricane Katrina, which whipped up tides and forced rain and seawater against a very fragile levee system that protected New Orleans. Since the city is 49% below sea level, when the man-made levees broke, flood waters moved in and inundated much of the city.
How much precipitation may cause flooding?
The amount varies widely for different areas. In some U.S. western deserts, or in some large urban areas, just a few minutes of strong rain will cause a flash flood in canyons and low-lying areas, both urban and rural. In areas prone to greater rainfall amounts, it often takes quite a bit more rain (sometimes a few days’ or weeks’ worth) to cause rivers to overflow and dams to fill up, raising concerns of those who live downstream. Areas that normally receive more rainfall have better natural drainage systems and are usually home to plants that readily absorb the extra water.
