Explanation: particle with sharp ends would have the slowest rate of deposition.

Downhill creep, also known as soil creep or commonly just creep, is the slow, downward progression of rock and soil down a low grade slope; it can also refer to slow deformation of such materials as a result of prolonged pressure and stress.

They may rush down a mountainside at speeds as great as 100 km (60 miles) per hour and can cause great damage to life and property. Boulders as large as houses have been moved by mudflows. Mudflow deposits are poorly sorted mixtures of silt, boulders, organic materials, and other debris.

Creep is a very slow mass movement that goes on for years or even centuries. You can’t see creep happening but leaning fences and poles and broken retaining walls show where it has taken place.

Creep is very slow movement of sediment down a slope. The process that lays down sediment in a new location is erosion.

Rockfalls

Human activities can increase landslide risks. They include clear-cutting, mining and quarrying, bad agricultural practices, and construction activities.

Debris flows are fast-moving landslides that are particularly dangerous to life and property because they move quickly, destroy objects in their paths, and often strike without warning.

Debris flows differ from slides because they are made up of “loose” particles that move independently within the flow. A slide is a coherent block of material that “slides” over a failure surface. Debris flows have larger particles – at least 50% of a debris flow is made up of sand-size or larger particles.

Ancient debris-flow deposits that are exposed only in outcrops are more difficult to recognize, but are commonly typified by juxtaposition of grains with greatly differing shapes and sizes. This poor sorting of sediment grains distinguishes debris-flow deposits from most water-laid sediments.

The houses which are in steep slopes are the most unsafe.

• If the house is near steep slopes, and landslides or debris flows have already occurred in the area, it is dangerous.
• Streams, wetlands, and slope erosion are all signs of potential issues.
• Slope conditions can also be determined by vegetative characteristics.

The worst landslide in U.S. history was in 1928, when as many as 500 people were killed after the collapse of the St. Francis Dam near Los Angeles, according to geologist Lynn Highland of the U.S.Geological Survey. National Landslide Information Center in Golden, Colo. There are many types of landslides.

An average of 25-50 people are killed by landslides each year in the United States. The worldwide death toll per year due to landslides is in the thousands. Most landslide fatalities are from rock falls, debris flows, or volcanic debris flows (called lahars).

Landslides are associated with hilly or mountainous landscapes. They are also common along coastlines and river valleys. Landslides occur most frequently in regions where climate and precipitation, bedrock and soil conditions, and slopes are susceptible to failure.

Many human-caused landslides can be avoided or mitigated. They are commonly a result of building roads and structures without adequate grading of slopes, poorly planned alteration of drainage patterns, and disturbing old landslides.

To be able to predict landslides, scientists have developed slope stability models to analyze the risk locally. More recently, NASA has created a preliminary algorithm to map landslide hazards globally using satellite measurements of rainfall, land cover and other surface variables.

landslide-ewas–early-warning-system Developed an early warning system that informs people about the likelihood of a landslide in a particular area. The system measures the water level in the ground, and then using a geotechnical mathematical model it evaluates the potential for a landslide.

The impact of a landslide can be extensive, including loss of life, destruction of infrastructure, damage to land and loss of natural resources. Landslide material can also block rivers and increase the risk of floods.

Synthetic aperture radar (SAR) now plays a key role in rapid landslide monitoring with its cloud-free, wide-swath, day-and-night observation capability. In particular, interferometric SAR (InSAR) analysis is widely used for early detection, continuous monitoring, and risk assessment of landslides (Strozzi et al.