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.

A brochure of the SES Action Guide: Emergency Management Australia's recommended steps to take in case of earthquake by .

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

A storm is simply a disturbed state of the atmosphere. The term strongly implies destructive or unpleasant weather conditions characterized by strong winds, heavy rain, snow, sleet, hail, lightning, or a combination of these occurrences. Each type of storm follows a particular life cycle and occurs in specific seasons when atmospheric conditions are right for its creation.

Tornadoes, or twisters, as they are sometimes called, can develop during thunderstorms. A tornado is a column of strongly rotating winds that may be shaped like a funnel or a pillar. The column reaches down from a cloud to touch the ground. It then moves along the ground at about 28 miles (45 kilometers) an hour, but the speed of a tornado’s winds may be 300 miles (500 kilometers) an hour. Tornadoes can destroy buildings and throw heavy objects high into the air.

Tornadoes are violent by nature. They are capable of completely destroying well-made structures, uprooting trees and hurling objects through the air like deadly missiles. A tornado is a violently rotating column of air extending from the base of a thunderstorm down to the ground. Tornado intensities are classified on the Fujita Scale with ratings between F0 (weakest) to F5 (strongest). Although severe tornadoes are more common in the Plains States, tornadoes have been reported in every state.

Tornadoes are simply borne out of supercell storms (Supercell tornadoes are more powerful than those that do not come from supercells). A supercell storm is a thunderstorm characterized by powerful updrafts. Example of non-supercell tornadoes are ‘gustnadoes’ and ‘landspouts’.

Hurricanes are strong storms that can be life-threatening as well as cause serious property-threatening hazards such as flooding, storm surge, high winds and tornadoes. Preparation is the best protection against the dangers of a hurricane. Know the difference between the threat levels and plan accordingly.

Hurricanes - also know as typhoons or cyclones - form in specific conditions. Different countries have different ways of preparing and responding to their devastating impact.

A Hurricane, like other natural disasters, is one that we all pause to listen to each time we hear of it on the news. This is because we have all seen the devastation that it can bring to us.

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. People on the beach or in low coastal areas need to be aware that a tsunami could arrive within minutes after a severe earthquake. The tsunami danger period can continue for many hours after a major earthquake. A tsunami can occur during any season of the year and at any time, day or night.

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.

An interactive guide that can save your life.

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. The sudden release of energy into the ocean created a tsunami (pronounced su-NAM-ee) event—a series of huge waves. The waves rushed outward from the center of the earthquake, traveling around 400 miles per hour. Anything in the path of these giant surges of water, such as islands or coastlines, would soon be under water.

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. "Seismic" implies an earthquake-related generation mechanism, but a tsunami can also be caused by a non-seismic event, such as a landslide or meteorite impact.

A flood is a high-water event in which water overflows its natural (or artificial) banks onto normally dry land. Floods have always been a part of life on Earth. Almost every culture has a legend about a great flood. To obtain access to transportation routes, fishing, and water for drinking, farming, and industry, many people have chosen to live near bodies of water. Most of the world’s large cities are situated on or near seacoasts, lakeshores, or rivers. River valleys often contain the richest farmland and easiest routes for railways and highways. However, living near water also makes one more vulnerable to the effects of flooding.

Floods are among the most frequent and costly natural disasters. Conditions that cause floods include heavy or steady rain for several hours or days that saturates the ground. Flash floods occur suddenly due to rapidly rising water along a stream or low-lying area.

Many of us have this idea that floods (or flooding) is simply, too much water around your house. People think that can be fun. Wrong. Flooding is a lot more than that.

A simple definition of flooding is water where it is not wanted. Another, more comprehensive definition of a flood is:
A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waters from the unusual and rapid accumulation or runoff of surface waters from any source.

Residents and businesses can find flood information and advice about flood risk and taking action, preparing for storms and flooding, Brisbane City Council's flood plans, policy and projects and recovery efforts from previous floods and severe weather events in 2011 and 2013.

Australia has a history of floods, causing devastating human and economic impact. Floods are a natural process influenced largely by the weather and driven by the amount of rainfall and length of time it falls. After heavy rainfall, rivers, creeks and catchments may overflow this type of flooding is most common in Australia and is known as riverine flooding.

A lack or insufficient amount of rain for an extended period of time is called drought. Drought causes water shortages, crop damage, streamflow reduction, and the depletion of groundwater and soil moisture, and has a serious negative impact on agriculture.

A drought is a period of abnormally dry weather that persists long enough to produce a serious hydrologic imbalance, causing, for example, crop damage and shortages in the water supply. The severity of a drought depends on the degree of moisture deficiency, the duration, and the size of the affected area.

The word ‘Drought’ is always a difficult one to define, because it is often used in more than one context. In simple terms, it is the absence of water for a long period of time, at a place where it is considered ‘not normal’ compared to its usual conditions.

Fires must be fought every day in most countries. Millions of fires start each year and cause great destruction of property and much human suffering. In the United States alone, in 1981, 6,800 people died in some of the almost 3 million fires that occurred and the cost of damaged or destroyed property was estimated at nearly 7 billion dollars.

More and more people are making their homes in woodland settings, rural areas or remote mountain sites. While residents in these areas enjoy the beauty of the environment around them, they also face the very real danger of wildfires.

Bushfire could be closer than you think. Prepare your home, property and family now and have your Bushfire Survival Plan in place before bushfire strikes.

Out of the many natural disasters we have, wild fires would be one that is very common, very difficult to fight, and maybe the most dangerous.

Bushfires and grassfires are common throughout Australia. Grassfires are fast moving, passing in five to ten seconds and smouldering for minutes. They have a low to medium intensity and primarily damage crops, livestock and farming infrastructure, such as fences. Bushfires are generally slower moving, but have a higher heat output. This means they pass in two to five minutes, but they can smoulder for days. Fire in the crown of the tree canopy can move rapidly.

ach year thousands of fires destroy or damage houses, sheds and garages, commercial and industrial buildings, vehicles and vast hectares of bushland throughout Western Australia (WA).

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.

A large mass of snow moving rapidly down a mountain slope is known as an avalanche. The snow breaks loose from its surroundings and quickly collects more snow as it plunges downslope. Avalanches can also be formed of rock, earth, or soil, but such events are usually called landslides.

By looking at avalanche cycles over the past 100-200 years, Peitzsch hopes to learn whether or not climate change will affect avalanche behavior in the future.

While avalanches are sudden, the warning signs are almost always numerous before they let loose. Yet in 90 percent of avalanche incidents, the snow slides are triggered by the victim or someone in the victim's party. Avalanches kill more than 150 people worldwide each year. Most are snowmobilers, skiers, and snowboarders.