Landslides and mudslides are two of the most common geological events, and while these two are often used interchangeably, there’s a subtle difference between them. These two events are largely catastrophic and have caused serious damage to lands, properties, and lives across the globe. You could call them one of Earth’s many banes. And while they can happen in any of the 50 states in the U.S., regions including the Appalachian Mountains, the Rocky Mountains, and the Pacific Coastal ranges are the most vulnerable.
What is the Difference Between a Mudslide and a Landslide
Like we mentioned before, mudslides and landslides are both common geological events but they aren’t exactly the same. While mudslides refer to a morbid movement of liquefied soil particles, landslides come with a movement of solid rocks, soil and other earth debris. A landslide is more of an overarching term describing the movement of a range of soil particles including rocks, boulders, soil particles, and other kinds of debris. They don’t always involve currents of water and they can either be slow or quick depending on the causative circumstances. Mudslides are a lot more specific as they involve a violent, rushing movement of liquefied soil particles like mud down a slope or hill. That pattern of movement is exactly why they are also known as mudflows and debris flows. One could think of them as a variant of landslides, and the difference between both lies in the fact that mudslides only carry mud and other smooth/liquefied soil particles. So, while we can loosely describe mudslides as subsets of landslides, they differ in content, speed and flows. Landslides carry various soil particles from solid rocks and boulders to fine soil particles. Mudslides, on the other hand, move only fine and clay-sized soil particles. Also, mudslides almost always involve a lot of water, while landslides can happen with very little liquid involved in the movement. Another difference between the two events is while mudslides always flow in a specific channel, there is no set channel for landslides. Landslides can come very slow or very fast, depending on the circumstances. Mudslides, on the other hand, are always fast and sudden, partly because they are often aided by currents of water.
Is a Mudslide a Landslide?
Mudslides are a kind of landslides and the major difference is in the specificity of the former’s content (fine and liquefied soil particles).
What Are The Types Of Landslides?
Like we mentioned before, a landslide is more or less, an overarching term and experts have classified it into four main types, namely:
Falls
These are the types of landslides characterized by a crumble of earth materials from a cliff or steep slope, which results in a sinister gathering of rocks and other debris at the base.
Topples
These are a form of landslides involving a forward rotational movement of a collection of rock, debris, and earth out of a slope. Topples are essentially a slope failure stemming from the base or around a pivot point of the rock.
Slides
Slides are perhaps the most common types of landslides and that explains why it is part of the composition of the general term, “landslides”. It involves a downslope movement of materials through a slip surface or rupture. There are two types of slides namely: rotational slides and translational slides. Rotational sides occur on a curved or spoon-shaped surface that allow for a rotational movement. Translational landslides, on the other hand, occur on flat and planar surfaces like a bedding plane. The translational landslide is the more calamitous of the duo because it happens on every scale without any stabilization.
Flows
Like the name implies, flows involve the downslope of materials in a distinctly fluid flow. And, as you probably guessed, the earlier-explained mudslides fall under this category. Other types include debris and rock avalanches.
What Causes Mudslides?
The major environmental culprit behind the occurrence of mudslides is erosion. Mudslides are often triggered when large currents of water cause quick soil erosion on a steep slope. The water could either be as a result of intense and continuous rainfall or a snowmelt at the top of a hill. Hence, once water meets soil, the soil becomes fluid and begins a disastrous downslope movement, also known as mudslides.
What Causes Landslides?
Landslides occur when the stability of a steep slope is tampered with by environmental factors like heavy rainfall, snowmelt, earthquake, volcano, erosion, and wildfires amongst others. They are also triggered by human activities like mining and extreme timber harvesting.
Effects Of Landslides
Landslides have myriads of catastrophic effects including:
Loss Of Human Life
People who live in mountainous and hilly areas prone to landslides often lose their lives when it does occur. For instance, the widely reported landslide that happened in Oso, Washington, in March 2014 claimed no less than 21 lives.
Infrastructural Damage
Landslides involve a forceful flow of earth materials including rock and debris and may cause extensive damage to roads, leisure centers, railways, and communication systems amongst others.
Serious Economic Decline
A landslide always causes damage to valuable properties and may, in some cases, wipe out entire communities, leading to serious rehabilitation costs. Experts estimate an annual loss of $1.5 billion due to landslides in the United States.
Alteration Of Landscape Aesthetics
Areas decimated by landslides often wear an ugly, morbid look that does not make for great scenery. The huge pile of debris alone removes any form of beauty the landscape used to bear.
Where Do Landslides Occur?
Landslides often occur in mountainous areas like the Rocky mountains, Appalachian Mountains, and the Pacific Coastal Ranges. The environmental agencies particularly list California, Washington, Oregon, Alaska, and Hawaii as the most susceptible states.
How is a Soil Creep Different From a Landslide?
Soil creeps and landslides are two of the most common forms of mass wasting. Soil creep refers to a particularly slow movement of soil materials down a slope due to gravity. The materials are often moistured and their movement is largely triggered by the force of gravity. With soil creeps, the movement is so slow that they can hardly be observed and they often take years to make a significant impact. They are major contributors to mass wasting because they often happen on great swaths of the earth. Landslides on the other hand, involve a rapid and seasonal movement of earth materials down the slope. Unlike the soil creeps, they are not continuous but rather seasonal. They are also very discernible unlike the soil creeps which take serious, patient, and extended observation to discern. Landslides occur on high-gradient slopes (steep slopes), while soil creeps operate on the low-gradient and shallow slopes. In addition, while soil creep is mostly a function of gravity, landslides are influenced by several factors to varying degrees. Essentially, soil creeps are slow, regular, and difficult to observe, while landslides are seasonal, rapid, and easily discernible.
