What constitutes a geophysical hazard?

A geophysical hazard is a natural event caused by geological or geomorphological processes that can cause damage or loss of life.

Geophysical hazards include events such as earthquakes, volcanic eruptions, tsunamis, and landslides. These hazards originate from the Earth's internal processes, which involve the movement and interaction of tectonic plates, the activity of volcanoes, and the shifting of the Earth's crust. For example, earthquakes occur when there is a sudden release of energy in the Earth's crust, causing the ground to shake. This can lead to buildings collapsing, roads cracking, and even tsunamis if the earthquake occurs under the sea.

Volcanic eruptions happen when magma from beneath the Earth's crust escapes to the surface, often explosively. This can result in lava flows, ash clouds, and pyroclastic flows, which are fast-moving currents of hot gas and volcanic matter. These eruptions can devastate nearby communities, destroy crops, and disrupt air travel due to ash clouds.

Tsunamis are large sea waves generated by underwater earthquakes, volcanic eruptions, or landslides. When these waves reach coastal areas, they can flood large areas, causing significant damage to property and loss of life. The 2004 Indian Ocean tsunami is a tragic example, where a massive underwater earthquake led to waves that affected multiple countries and resulted in over 230,000 deaths.

Landslides occur when rock, earth, or debris moves down a slope due to gravity. They can be triggered by factors such as heavy rainfall, earthquakes, volcanic activity, or human activities like deforestation. Landslides can bury homes, roads, and entire villages, making them a serious hazard in mountainous and hilly regions.

Understanding geophysical hazards is crucial for predicting and mitigating their impacts, helping to protect communities and save lives.