Ground disturbances are sudden and dramatic changes in the earth’s surface, such as earthquakes, landslides, rockfalls, debris flows, and glacier outbursts. Ground disturbances can cause significant and sometimes catastrophic damage to buildings, utilities, and other infrastructures. This article discusses the causes of ground disturbances and their potential hazards. Understanding the factors that lead to these types of conditions is essential for anyone working in an area that could be at risk for a ground event. In addition to outlining the different types of ground disturbances and their causes, this article also includes examples of some of the most devastating ground events in recent history. Finally, it also discusses prevention and mitigation strategies to help reduce the likelihood of these events occurring in the future.
What is a ground event?
A ground event is a sudden and dramatic change in the earth’s surface that can cause significant and often catastrophic damage to buildings, infrastructures, and utilities. Ground events can be caused by a number of different geologic processes, including earthquakes, volcanoes, floods, tsunamis, landslides, and even meteorite impacts. Each of these processes has its own unique characteristics, but they all cause the same type of ground event: a sudden and dramatic change in the earth’s surface that can cause significant and often catastrophic damage to buildings, infrastructures, and utilities.
Types of Ground Disturbances
There are many different types of ground disturbances, and it is important to understand what each one is and how it develops. The following is a brief explanation of each type of ground disturbance:
An earthquake: An earthquake is a sudden and rapid change in the movement or pressure within a fault (or fault zone). Faults are fractures in the earth’s crust that run for great distances, and earthquakes can be a result of one of these faults shifting and extending. The most common instruments used to detect earthquakes are seismographs, which are large, sensitive devices that can record the vibrations caused by an earthquake.
A volcano: A volcano is a structure that, when active, erupts molten material from deep within the earth’s crust. The material flows out of the volcano and into the surrounding environment, leaving a large, often heavily polluted crater. Volcanos can cause the ground above them to collapse, resulting in a large-scale ground event.
A flood: A flood is a large-scale event that occurs when a large amount of water is released from a body of water in a short amount of time. Floods can be the result of many different mechanisms, including earthquakes, volcanoes, and even tsunamis. When a flood occurs, the water flows over the land, often causing significant damage to buildings and infrastructures.
Causes of Ground Events
There are many different factors that can cause a ground event, including natural events (such as earthquakes or volcanic eruptions) and human activities (such as mining or construction). The factors that lead to a specific type of ground event vary, but certain elements are common across almost every type of event. Before discussing the causes of ground events, it’s important to understand what causes a tectonic event. A tectonic event is a type of geologic event that occurs as a result of the movement of large masses of rock, known as tectonic plates.
Tectonic plates are large masses of rock that float on the planet’s mantle, which is the thick layer of hot rock covering the earth’s surface. These plates are responsible for the movement and upheaval of various landforms, including mountains, deserts, and even vast underwater areas. When two plates collide, the energy released is known as an earthquake.
Most earthquakes are a result of the movement of tectonic plates. However, there are several other causes of tectonic events, including the following:
Deformation: Deformation is the result of tectonic plates moving and sliding over each other, resulting in a sudden and dramatic change in the earth’s surface. For example, the eastern part of the United States is a result of the North American tectonic plate sliding over the African plate. When tectonic plates shift and slide over each other, they cause the earth’s surface to buckle and form a mountain range. Deformation can be caused by earthquakes, volcanoes, or other geologic processes.
Volcanic explosion: A volcanic explosion is a sudden and dramatic explosion and release of gases, molten rock, and other materials from the interior of a volcano. Volcanic explosions can be the result of an underground build-up of pressure, which can be caused by the movement of tectonic plates or an earthquake.
Landslide: A landslide is a large mass of rock or soil that falls down a steep slope and often covers a wide area. A large-scale event, which can be the result of an earthquake, volcanic explosion, or other geologic event, can trigger a large-scale landslide.
Debris flow: A debris flow is a type of extreme flow that is often triggered by an earthquake or volcanic explosion. A debris flow is a large-volume flow of water, mud, and other materials that often follows a path of least resistance and can cause extreme damage.
Once you understand the causes of ground events, you can better identify and prepare for them. It is important to know the characteristics of potential ground events so you can better prepare for them and take the necessary precautions. Some of the most frequent causes of ground events are discussed below:
Megaquake
A megaquake is a very large earthquake that can cause a significant amount of damage. A megaquake can occur due to a large-scale event, such as the movement of tectonic plates or an earthquake, or as the result of a series of smaller earthquakes over a long period of time. A large-scale event can cause the ground to shift, resulting in a massive amount of energy being released. This sudden and powerful shift is a major indicator of a potential large-scale event, such as a megaquake.
Volcanic Eruption
A volcanic eruption is a very large-scale event that can cause a significant amount of damage. The most common forms of volcanic eruptions are pyroclastic flows and lahars (or volcanic mudflows). A pyroclastic flow is a fast-moving mixture of ash, gas, and rock that travels at high speeds and can cause significant damage. An explosive eruption from a volcano can also trigger a large-scale debris flow. A debris flow is a very large flow of materials down a steep slope that often travels at very high speeds. Volcanic eruptions can occur both near the surface and deep within the earth’s crust.