In the early hours of August 2, 2014, nearly 2 kilometers of hillside collapsed in rugged northern Nepal. Image: NASA.


The term “landslide” refers to a variety of processes that result in the downward and outward movement of slope-forming materials, including rock, soil, artificial fill, or a combination of these. The materials may move by falling, toppling, sliding, spreading, or flowing (UNDRR).

A landslide is a downslope movement of rock or soil, or both, occurring on the surface of rupture, either curved (rotational slide) or planar (translational slide) rupture, in which much of the material often moves as a coherent or semi coherent mass with little internal deformation (USGS).

Facts and figures

According to the International Disaster Database of the Centre for Research on the Epidemiology of Disasters, in the period from 2000 to 2014, 26,000 persons have lost their lives because of landslides and flash floods while the economic losses amounted to over US$ 40 billion (OFDA/CRED).

Landslides can be classified into different types on the basis of the type of movement and the type of material involved. In brief, material in a landslide mass is either rock or soil (or both); the latter is described as earth if mainly composed of sand-sized or finer particles and debris if composed of coarse fragments. The type of movement describes the actual internal mechanics of how the landslide mass is displaced: fall, topple, slide, spread, or flow. Thus, landslides are described using two terms that refer respectively to material and movement, that is rockfall, debris flow, and so forth. Landslides may also form a complex failure encompassing more than one type of movement that is, rock slide and debris flow (USGS).

The primary driving factor of landslides is gravity acting on a portion of a slope that is out of equilibrium. The following are some of the major landslide triggering mechanisms:

  • River erosions, glaciers, or ocean waves
  • Weakening of rock and soil slope properties through water saturation by snowmelt or heavy rains
  • Stresses, strains and excess of pore pressures induced by the inertial forces during an earthquake (earthquakes of magnitude greater than or equal to 4.0 can trigger landslides)
  • Volcanic eruptions with the production of loose ash deposits that may become debris flows (known as lahars) during heavy rains
  • Stockpiling of rock or ore, from waste piles, or from man-made structures
  • Changes of the natural topography caused by human activity (UNDRR).

Related content on the Knowledge Portal

SAM Satellite

SPOT-7 is a high-resolution wide-swath imaging spacecraft built and operated by Airbus Defence and Space taking over the majority of Spot Image after the government support of the SPOT program was terminated. SPOT-6 – launched in 2012 – and SPOT-7 are identical spacecraft, based on the AstroSat-250 satellite bus and use the NAOMI (New AstroSat Optical Modular Instrument) payload to acquire optical imagery to ensure the continuity of SPOT data, building on experience gained through previous missions, particularly SPOT-5 that launched in 2002.
The SPOT-7 spacecraft is built for a ten-year mission featuring two NAOMI cameras to cover a 60-Kilometer ground swath, 120km using single-pass mosaic imaging. Overall, the satellite can achieve a resolution of two meters in panchromatic and eight meters in multispectral mode covering the visible and near-infrared spectral bands.

Instrument: 2x NAOMI (New AstroSat Optical Modular Instrument)
- 60km swath width... read more

Launch date:

Launched in June 2014 with an expected life-time of more than 7 years, Deimos-2 is an agile, high resolution satellite that became the only European fully-private satellite capable of providing sub-metric multispectral imagery. From a 620-km ascending sun-sync orbit, it has a 12/24-km swath (depending on the imaging mode), stereo-par capability and ±45º off-nadir tilting capacity. Its multispectral camera has a panchromatic and 4 spectral bands (R,G,B,NIR), at 10 bits. This allows Deimos-2 to provide 75-cm pan-sharpened imagery.

Deimos-2 was designed to provide a cost-effective and highly responsive service to cope with the increasing need of fast access to sub-metric imagery. As evidence of this, it provides near-real time image tasking, downloading, processing and delivery to the end user. It has a collection capacity of more than 150,000 km2/day with a two-day average revisit time worldwide. The whole Deimos-2 ground segment has been completely developed in-house by... read more

Launch date:

ALOS-2 (Advanced Land Observation Satellite 2) is the follow-on JAXA L-SAR satellite mission of ALOS (Daichi) approved by the Japanese government in late 2008. The overall objective is to provide data continuity to be used for cartography, regional observation, disaster monitoring, and environmental monitoring.
The post-ALOS program of JAXA has the goal to continue the ALOS (nicknamed Daichi) data utilization - consisting of ALOS-2 (SAR satellite) and ALOS-3 (optical satellite) in accordance with Japan's new space program.

The state-of-the-art L-band Synthetic Aperture Radar (SAR) aboard ALOS-2, which is an active microwave radar using the 1.2 GHz frequency range, which, in responding to society's needs, has enhanced performance. The SAR is capable of observing day and night, and in all weather conditions.

ALOS-2 has a spotlight mode (1 to 3 m) and a high resolution mode (3 to 10 m). It allows comprehensive monitoring of disasters... read more

Launch date:

KOMPSAT-5 is an earth observation satellite equipped with Korea's first all-weather SAR.
The SAR mounted on KOMPSAT-5 emits microwaves to an object on the ground and synthesizes the reflected signal to produce an image. It enables ground observation even during nighttime and poor weather conditions.
As the SAR image can supplement the optical camera, which can record only the visible light spectrum, it is utilized in mutual supplementary operations with the high-resolution optical images of KOMPSAT-3 and KOMPSAT-3A.
KOMPSAT-5 observes the Korean Peninsula four times a day. The transmitted image data are used for public safety, natural disaster forecasts, land/resource management and environmental monitoring.

The primary mission of the KOMPSAT-5 system is to provide high resolution mode SAR images of 1 meter resolution, standard mode SAR images of 3 meter resolution and wide swath mode SAR images of 20 meter resolution with viewing conditions of the incidence... read more

Launch date:

Resurs-P1 is a Russian Earth observation satellite designed and developed at TsSKB Progress (Progress State Research and Production Space Center) in Samara, Russia. Roskosmos is funding the project (owner and operator of the spacecraft under the Russian Federal Space Program), the commercial data distributor is Sovzond JSC of Moscow. The spacecraft is operated by NTs OMZ (Research Center for Operational Earth Monitoring), Moscow, Russia.

Resurs-P1 is meant to replace the Resurs-DK, a previous generation spacecraft, which was launched on June 15, 2006.

Resurs-P carries the Geoton-L1 hyperspectral imaging payload as the main imaging instrumet. The optics have an apperture of 0.5 m and provides images with a ground resolution of 1.0 m in panchromatic mode and a resolution of 3 to 4 m in color mode. The Geoton-L1 system has 7 passbands and a 216-channel hyperspectral imager.

Aditionallym the KShMSA wide field multispectral camera is... read more

Launch date:

Gaofen-1 (gao fen = high resolution) is the first of a series of high-resolution optical Earth observation satellites of CNSA (China National Space Administration), Beijing, China. The civilian HDEOS (High-Definition Earth Observation Satellite) program was proposed in 2006, it received government approval and was initiated in 2010. China plans to launch six HDEOS spacecraft between 2013 and 2016. The major users of the observation data will be the Ministry of Land and Resources, Ministry of Environmental Protection, and the Ministry of Agriculture.
The GF-1 spacecraft was launched on April 26, 2013 on a CZ-2D (Long March -2D) vehicle from the JSLC (Jiuquan Satellite Launch Center) in northwest China.

PMC (PAN and Multispectral camera)
WFI (Wide Field Imager)

Launch date:

Landsat 8 launched on February 11, 2013, from Vandenberg Air Force Base, California, on an Atlas-V 401 rocket, with the extended payload fairing
 (EPF) from United Launch Alliance, LLC. The Landsat 8 satellite payload consists of two science instruments—the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). These two sensors provide seasonal coverage of the global landmass at a spatial resolution of 30 meters (visible, NIR, SWIR); 100 meters (thermal); and 15 meters (panchromatic).
Landsat 8 was developed as a collaboration between NASA and the U.S. Geological Survey (USGS). NASA led the design, construction, launch, and on-orbit calibration phases, during which time the satellite was called the Landsat Data Continuity Mission (LDCM). On May 30, 2013, USGS took over routine operations and the satellite became Landsat 8. USGS leads post-launch calibration activities, satellite operations, data product generation, and data archiving at the Earth Resources... read more

Launch date:

Launched in December 2011, Pleiades is a constellation of two very-high-resolution satellites capable of acquiring imagery of any point on the globe in under 24 hours for civil and military users.
Pleiades has been observing and mapping Earth’s surface at a resolution of just 70 cm every day since December 2011. Comprising the Pleiades 1A and Pleiades 1B satellites, this space imaging system complements the capabilities of the SPOT satellites, which have a wider field of view than Pleiades but lower spatial resolution. What’s more, as Pleiades 1A and 1B are in the same orbit, together they can image anywhere on Earth in less than 24 hours. Pleiades imagery is used for both civil and military applications, for example to track urban expansion, monitor the planet’s active volcanoes or assist road and railway routing, and to locate adversaries’ military installations for mission planning. Pleiades’ key asset is an extremely sensitive optical instrument that reduces the exposure... read more

Launch date:

SJ-9 (Shi Jian = Practice) is a technology demonstration formation flight mission of CNSA (China National Space Administration), consisting of two minisatellites of different sizes and capabilities, SJ-9A and SJ-9B. The overall mission concept is to demonstrate the functionality of a range of newly developed formation flying techniques and components and to validate the formation flight GNC (Guidance, Navigation and Control) algorithms and strategies of the system configuration.
SJ 9B carries the LWIR (Long Wave Infrared) Camera as a technology experiment. The goal of the LWIR camera is to test mainly the functions of the instrument such as the focal-plane component and the long-life Stirling cryocooler which is designed to function as an autonomic research and development component. The camera features low-temperature optics. The operational temperature of optical system is kept in the range of -35ºC to -20ºC.

Instrument: LWIR (Long Wave... read more

Launch date:

SJ-9 (Shi Jian = Practice) is a technology demonstration formation flight mission of CNSA (China National Space Administration), consisting of two minisatellites of different sizes and capabilities, SJ-9A and SJ-9B. The overall mission concept is to demonstrate the functionality of a range of newly developed formation flying techniques and components and to validate the formation flight GNC (Guidance, Navigation and Control) algorithms and strategies of the system configuration.
SJ 9A is based on the CAST-2000 bus. It conducts in-orbit experiments for electric propulsion, high-precision- and high-stability control systems, high-efficienent power supply and advanced thermal control technology. The satellite features also instruments for Earth observation and component tests of indigenously developed technology.

Instruments: High-performance small camera
- integrated panchromatic and multispectral design
- swath width: 30km
-... read more

Launch date:


Hazard group

Terms in the same hazard group

Zircon - This is a contributing Drupal Theme
Design by WeebPal.