Types of landslide, and what sets one off
PHIVOLCS names five ways the ground moves: fall, topple, slide, spread and flow. Which one you are looking at decides how fast it arrives and how far from the slope it reaches.
Written for the Philippines. Pagguho ng lupa ang tawag dito sa Filipino.
What a landslide is
PHIVOLCS defines it as the mass movement of rock, soil and debris down a slope due to gravity. It happens when the driving force becomes greater than the resisting force. It is a natural process on steep slopes, the movement may be anything from very slow to rapid, and it can affect areas both near and far from the source.
That last part is the one worth holding on to. Being off the slope is not the same as being out of the way.
Source: PHIVOLCS, Introduction to Landslide. Read 23 September 2026. The definition, the four materials, the four natural triggers, the five kinds of movement and the six Philippine cases on this page are all from that page. PHIVOLCS illustrates each kind of movement with an unlabelled diagram and does not define it in words, so the descriptions here say what their diagram shows.
What actually comes down
PHIVOLCS lists four things a landslide can be made of. The fourth one is not a figure of speech.
- Soil
- Debris
- Rock
- Garbage
The five kinds of movement
PHIVOLCS names these five and draws each one. It does not describe them in words, so what follows is a description of their drawings. The diagrams here were made for this page from those originals.
- Fall
- Material breaks away from a steep face and drops. The diagram shows blocks leaving the top of the slope and travelling mostly through the air, bouncing down and coming to rest in a heap at the bottom.
- Topple
- The block never leaves the slope. The diagram shows tall slabs standing on the hillside, each one pivoting forward about its own base, the way a wall tips over rather than slides.
- Slide
- One body of material moves as a unit along a surface of failure. The diagram PHIVOLCS uses shows that surface curved rather than flat, so the mass drops at the back and tilts as it goes. A slump is this shape.
- Spread
- The ground pulls apart sideways on gentle ground. The diagram shows a row of blocks all moving the same way along a flat surface, with gaps opening between them rather than a single mass sliding off a slope.
- Flow
- The material behaves like a liquid. The diagram shows a tongue of it running down a hillside, narrow where it is confined and spreading out where the ground flattens at the bottom.
Source: PHIVOLCS, Introduction to Landslide. Read 23 September 2026.
What sets one off
These are the four natural triggers PHIVOLCS lists.
- Intense rainfall
- Weathering of rocks
- Ground vibrations created during earthquakes
- Volcanic activity
Their page also has a heading for man-made triggers with nothing listed under it. Rather than fill that in from somewhere else and leave their name on it, this page leaves it empty too. Two of the six landslides below are man-made in origin, and those are theirs, so those are the ones named here: a cut slope, and a pile of solid waste.
Source: PHIVOLCS, Introduction to Landslide. Read 23 September 2026.
Six that happened here
Most of what is written about landslide types online is illustrated with slopes in the United States or the United Kingdom. These six are the ones PHIVOLCS photographed, with the place and the date they give for each.
- Rockslide and debris avalanche
- Brgy. Guinsaugon, St. Bernard, Southern Leyte. February 2006.
- Rain-induced landslide
- Panaon Island, Southern Leyte. December 2003.
- Rain-induced debris flow
- Brgy. Mayana, Barili, Cebu. December 2014, during Tropical Storm Seniang.
- Earthquake-induced rockslide
- Brgy. Conalum, Argao, Cebu. October 2013, during the magnitude 7.2 Bohol earthquake.
- Landslide on a cut slope
- Brgy. Manipis, Talisay City, Cebu. September 2015.
- Solid-waste slide
- Brgy. Payatas, Quezon City, Metro Manila. July 2000.
Source: PHIVOLCS, Introduction to Landslide. Read 23 September 2026.
What to do about one
This page is about what a landslide is. What to do before, during and after one is on the flood guide, because the same days of rain produce both, and a house at the foot of a slope near a creek is exposed to the two of them at once.