The sudden shaking of the ground that occurs when masses of rock change position below Earth’s surface is called an earthquake. The shifting masses send out shock waves that may be powerful enough to alter the surface, thrusting up cliffs and opening great cracks in the ground.

An earthquake is a sudden, rapid shaking of the earth caused by the breaking and shifting of rock beneath the earth’s surface. Earthquakes strike suddenly, without warning, and they can occur at any time of the year, day or night. Forty-five states and territories in the United States are at moderate to very high risk of earthquakes, and they are located in every region of the country. Learn how to prepare for an earthquake with the following safety tips provided by the American Red Cross.

Earthquakes are caused by the release of built-up pressure inside the Earth's crust. An earthquake's power is measured on the Richter scale using an instrument called a 'seismometer'.
The effects of an earthquake can be devastating - they can destroy settlements, change landscapes, and cause many deaths.

An earthquake is what happens when two blocks of the earth suddenly slip past one another. The surface where they slip is called the fault or fault plane. The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter.

Earthquakes are the vibrations caused by rocks breaking under stress. The underground surface along which the rock breaks and moves is called a fault plane.

An earthquake is a sudden shaking of the Earth's surface caused by rock breakage deep within the Earth. This is the result of stresses that have built up within the Earth's brittle crust.

The Victoria State Emergency Service (VICSES) is the control agency for earthquakes in Victoria, which means that we are responsible for planning for earthquakes and for managing responses if an earthquake does occur.

In Alaska in 1964, a magnitude 9.2 earthquake jarred the earth so strongly it caused fishing boats to sink in Louisiana. What causes the ground tremble like that? The answer is simple. The Earth's surface is on the move.

The ground shakes, buildings tumble and the earth heaves and cracks. Serious earthquakes are terrifying and dangerous, but are rare in the U.S. But why do earthquakes happen? The earth is made up of four layers – the inner core, outer core, mantle and crust. The mantle and crust are a thin skin compared to the other layers. The mantle is about 1,750 miles thick, while the crust is only about 8 miles thick. This thin skin is broken into pieces called tectonic plates. The plates are like puzzle pieces, floating on top of the Earth’s inner core. Sometimes the pieces slide under or against each other and become stuck.

urn on the TV or read the newspapers and almost always there is something devastating happening somewhere as a result of sheer nature's power. Examples of such natural occurrences are hurricanes, tornados, wildfires, volcanic eruptions, flooding, earthquakes and tsunamis. These are usually not caused directly by humans, but their effects live with us for a long time

One of the most powerful and feared natural disasters, the large and destructive water wave known as a tsunami can challenge a jet airplane for speed. Near the coast it can beat a three-story building for height. These waves pack enough energy to destroy an entire coastal community in moments. Underwater earthquakes and volcanic eruptions are the most common causes of tsunamis.

Tsunamis are a series of large ocean waves generated by major earthquakes beneath the ocean floor or major landslides into the ocean. When the waves enter shallow water, they may rise to several feet or, in rare cases, tens of feet, striking the coast with devastating force.

A tsunami is a huge wave, usually caused by volcanic or earthquake activity under the ocean, which can eventually crash onto the shoreline. The effects on a community can be devastating.

Interactive Tsunami Preparedness website

The Victoria State Emergency Service (VICSES) is the control agency for tsunami in Victoria, which means that we are responsible for planning for tsunami and for managing response if a tsunami does occur.

Tsunami (pron: 'soo-nar-me') is a Japanese word; 'tsu' meaning harbour and 'nami' meaning wave. The phenomenon is usually associated with earthquakes, landslides or volcanic eruptions in, or adjacent to oceans, and results in sudden movement of the water column. Until recently tsunami were called tidal waves, even though the event has nothing to do with tides.

A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore.

The people in south Asia had no warning of the next disaster rushing toward them the morning of December 26, 2004. One of the strongest earthquakes in the past 100 years had just destroyed villages on the island of Sumatra in the Indian Ocean, leaving many people injured. But the worst was yet to come—and very soon. For the earthquake had occurred beneath the ocean, thrusting the ocean floor upward nearly 60 feet.

Tsunami is a Japanese word with the English translation: "harbour wave". In the past, tsunamis have been referred to as "tidal waves" or "seismic sea waves". The term "tidal wave" is misleading; even though a tsunami's impact upon a coastline is dependent upon the tidal level at the time a tsunami strikes, tsunamis are unrelated to the tides. (Tides result from the gravitational influences of the moon, sun, and planets.) The term "seismic sea wave" is also misleading.

A tsunami is most often triggered by undersea earthquakes that cause massive changes to the ocean floor. Tsunami can also be caused by seismic events, landslides, or even asteroid impacts.

A mass of rock or soil moving down a slope is known as a landslide. A similar event involving snow is called an avalanche. Landslides differ in their type, speed, extent, and destructiveness. In some types, such as a rockfall, the material separates from the slope and falls rapidly. In a mudflow or debris flow, loose soil, rock fragments (known as debris), or volcanic ash becomes saturated with water and suddenly pours downslope like a fluid, often very fast. Such flows can rush down a mountainside at speeds as great as 200 miles (320 kilometers) per hour, but most flow at about 30–50 miles (50–80 kilometers) per hour. In some other kinds of landslides, the material shifts down at a moderate or slow speed, sometimes even creeping imperceptibly for years.

Landslides have occurred in almost every state and can cause significant damage. The term landslide describes downhill earth movements that can move slowly and cause damage gradually, or move rapidly, destroying property and taking lives suddenly and unexpectedly. Most landslides are caused by natural forces or events, such as heavy rain and snowmelt, shaking due to earthquakes, volcanic eruptions and gravity. Landslides are typically associated with periods of heavy rainfall or rapid snowmelt and tend to worsen the effects of flooding. Areas burned by forest and brush fires are also particularly susceptible to landslides.

A landslide is the movement of rock, debris or earth down a slope. They result from the failure of the materials which make up the hill slope and are driven by the force of gravity. Landslides are known also as landslips, slumps or slope failure.

Altitude sickness, also known as mountain sickness, occurs when a person who is accustomed to low elevations travels to higher elevations, typically those above 8,000 feet (2,400 meters). Symptoms can range from shortness of breath to a life-threatening accumulation of fluids in the lungs or the brain. Altitude sickness is the body’s reaction to the decreased atmospheric pressure and lower concentration of oxygen that exist at high altitudes. The cause of altitude sickness was first correctly described in 1878, when the French physiologist Paul Bert demonstrated that the symptoms were caused by a lack of oxygen reaching the body’s tissues. Mountain climbers, hikers, skiers, and people who live at high elevations are most likely to suffer from altitude sickness

When you’re flying, mountain climbing, hiking, or driving at a high altitude, your body may not get enough oxygen. The lack of oxygen can cause altitude sickness, which often shows up as headaches and insomnia. Altitude sickness generally occurs at altitudes of 8,000 feet and above. People who aren’t accustomed to these high altitudes are most vulnerable.

Altitude sickness occurs when you cannot get enough oxygen from the air at high altitudes. This causes symptoms such as a headache, loss of appetite, and trouble sleeping. It happens most often when people who are not used to high altitudes go quickly from lower altitudes to 8000 ft (2438 m) or higher. For example, you may get a headache when you drive over a high mountain pass, hike to a high altitude, or arrive at a mountain resort.

Altitude sickness or mountain sickness is caused by ascending too rapidly, which does not allow the body enough time to adjust to reduced oxygen and changes in air pressure. Symptoms include headaches and vomiting. Altitude sickness can be harmful or fatal.