---
title: "All mass movements are landslides"
subject: "Engineering Geology I"
chapter: 6
key: "semester_3/engineering_geology_i:all-mass-movements-are-landslides"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/all-mass-movements-are-landslides
site: BCT Engineering
---

# All mass movements are landslides

Engineering Geology I · Chapter 6: Physical Geology

- Asked in: 2063 Baisakh (old course), 3 marks
- Video: [What is Mass Wasting? | Geography | iKen | iKenEdu | iKenApp](https://www.youtube.com/watch?v=k3IJKJQ2pAY) — Iken Edu
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/all-mass-movements-are-landslides
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-6

## Question

Justify: "All mass movements are landslide but all landslides are not mass movement".

## Short answer

The correct relationship is that all landslides are mass movements, but not all mass movements are landslides. Mass movement includes falls, topples, flows, creep and spreads; landslides are only the subset that slide along a distinct slip surface.

## Answer

**Note on the statement:** the standard teaching is the other way round: *all landslides are mass movements, but not all mass movements are landslides.* Landslide is only one group within the larger family of mass movement, as shown below. The reasoning is as follows.

- **Mass movement** is any downslope movement of soil, rock or debris under gravity. It includes **falls, topples, slides, spreads, flows and creep** (Varnes, 1978).
- **Landslide** (in the strict sense) means sliding along a defined slip surface (rotational or translational slide). In popular and common usage "landslide" is used for nearly all slope movements.
- Thus every landslide is a form of mass movement, because it is a gravity-driven downslope movement.
- Some mass movements are not landslides: **creep** (very slow, no distinct slip surface), **rock fall**, **topples**, **debris flow** and **mud flow** (move like a fluid) and **solifluction**.

```text
   MASS MOVEMENT
   +---------------------------------+
   | fall  topple  flow  creep spread|
   |        +------------+           |
   |        | LANDSLIDE  |           |
   |        | (slides)   |           |
   |        +------------+           |
   +---------------------------------+
```

So landslide is a subset of mass movement; the reverse is not true.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is the standard relation between landslide and mass movement?
   A. All mass movements are landslides
   B. Landslide and mass movement are unrelated
   C. No landslides are mass movements
   D. All landslides are mass movements, but not all mass movements are landslides
   Answer: D. Landslide is a subset of the larger mass-movement family. (Key point: Correct relation)

2. Mass movement includes:
   A. Falls, topples, slides, spreads, flows and creep
   B. Only sliding along a surface
   C. Only rock falls
   D. Only river erosion
   Answer: A. Varnes (1978) classified these types. (Key point: Mass movement)

3. Which is a mass movement that is not a landslide in the strict sense?
   A. Rotational slide
   B. Creep
   C. Planar slide
   D. Translational slide
   Answer: B. Creep is very slow with no distinct slip surface. (Key point: Non-landslide example)

4. In the strict sense, landslide means:
   A. Any slope movement including flows and creep
   B. Movement of water only
   C. Sliding along a defined slip surface
   D. Fall through air only
   Answer: C. Popular usage widens it to nearly all slope movements. (Key point: Strict meaning)

## Related in Engineering Geology I

- [Define mass movement and its classification](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Adefine-mass-movement-and-its) — Engineering Geology I, chapter 6, asked 5×
- [Landslide causes and slip surface techniques](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Alandslide-causes-and-slip-surface) — Engineering Geology I, chapter 6
- [Preventive measures for landslide and rock slope](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Apreventive-measures-for-landslide-and) — Engineering Geology I, chapter 6, asked 4×

## Related in other subjects

- [Varnes classification of landslides](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Avarnes-classification) — Engineering Geology II, chapter 5, asked 14×
- [Mass movement and its mechanism](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Amass-movement-mechanism) — Engineering Geology II, chapter 5, asked 11×
- [Justify not self starting; two starting methods](https://www.bctengineer.com/question.md?key=semester_5%2Felectric_machines_ii%3Amotor-starting-two-methods) — Electric Machines II, chapter 2
- [Factors of mass movement](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Afactors-of-movement) — Engineering Geology II, chapter 5