I thought facts about landslides would make an interesting topic. Landslides are not something new on our planet. And, we shouldn’t expect this natural phenomenon to stop one day. As long as there is a force of gravity on earth, landslides will continue to occur causing damages all around the world.
15 interesting facts about Landslides
- A landslide is a general term given to the natural movement of land, rocks, mud, and debris down a slope with a varying speed.
- Snowmelt, rainfall, earthquake, volcano, and change of water levels can cause a landslide, or at least they can accelerate the process.
- Human activities can contribute to the occurrence of landslides. For instance, mining, vibrations from traffic, deforestation, urbanization, and changing of drainage patterns can effect to a land structure.
- Annually, about 25-30 people die in the United States because of landslides. Globally, that number goes well above a thousand.
- NASA manages the worldwide map of potential landslide areas. You can watch it here.
- Earthquakes can lead to underwater landslides, which are also known as submarine landslides. Although they happen underwater, they can still damage coastal areas by causing a tsunami.
- Storegga slide was one of the largest known submarine slides in the world, which took place in the Norwegian sea in approximately 6225-6170 BCE. A landmass, believed to be 600 and 840 cubic miles (966 – 1352 km) in size, slid off Norway’s continental shelf. The landslide caused a giant tsunami which hit the coast of Norway with 30-35 feet (9-10.7 m) and Shetland islands with 60-90 feet (18-27 m) waves. The cause of the landslide believed to be a glacial melting.
- The largest subaerial landslide, called Heart Mountain Landslide, took place in the territory of Wyoming about 50 million years ago. A slab of Madison limestone, which is believed to be 400 square miles (644 sq km) in size with the thickness of 1600 ft (488 m) broke off from the Willwood formation.
- Landslides have several types, such as debris slide, earth flow, debris flow, sturzstrom (rock avalanche), etc… Landslide types are categorized by observing their natural movements (flow, fall, slide) and materials involved (sediment, debris, rock, mud etc..)
- Landslides were also detected in Venus and Mars. However, the largest landslide occurred on our planet. The largest landslide that took place on Mars was 60 miles (96.5 km) long, the one in Venus was 30 miles (48 km) long.
- Every year landslides cause over 3.5 billion dollars in damage in the United States.
- A debris flow can move with the speed up to 100 miles per hour. Nevertheless, in order to reach that kind of high speed, debris flow must come down from very steep slopes.
- Mudslide is also a type of landslide. Usually, heavy rainfall, flooding, ice melting trigger a mudslide. This muddy flow can destroy everything in its path. For instance, The Venezuelan Mudslide of 1999 was the deadliest mudslide in modern history. It killed somewhere between 10,000 to 30,000 people and claimed thousands of homes, led to the evacuation of 190,000 people, causing billions of dollars in damage.
- Early warning about landslides is usually issued in two ways. Scientists can detect landslides remotely by using a sensitive seismograph if a landmass is already in a movement. The other way is predicting a landslide in potential areas by looking at radar precipitation estimates.
- A forest fire can also pave the way for a landslide. After a fire, the soil gets compacted. As result, water does not soak into the water as usual. Excess water flows across the land washing everything on its path down a hill.
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