---
title: "Short note: Main Frontal Thrust"
subject: "Engineering Geology I"
chapter: 7
key: "semester_3/engineering_geology_i:short-note-main-frontal-thrust"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/short-note-main-frontal-thrust
site: BCT Engineering
---

# Short note: Main Frontal Thrust

Engineering Geology I · Chapter 7: Geology of Nepal

- Asked in: 2068 Baisakh, 3 marks
- Video: [Himalaya's Fold mountains and Thrust boundaries explained with animation (part 2/3) | UPSC](https://www.youtube.com/watch?v=mF58L2J0FK4) — Zeta Axis (UPSC-SSC)
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/short-note-main-frontal-thrust
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-7

## Question

Write a short note on the Main Frontal Thrust.

## Short answer

The Main Frontal Thrust (MFT), also called Himalayan Frontal Thrust (HFT), is the southernmost major thrust of the Nepal Himalaya. It separates the Siwalik hills from the Terai plain and is the youngest and most active thrust, thrusting Miocene-Pleistocene rocks southward over Quaternary alluvium. It poses earthquake hazards, surface rupture, and slope instability for engineering structures.

## Answer

The **Main Frontal Thrust (MFT)**, also called the **Himalayan Frontal Thrust (HFT)**, is the southernmost major thrust of the Nepal Himalaya. It separates the **Siwalik** zone in the north from the **Terai (Indo-Gangetic) plain** in the south and runs roughly east-west along the foot of the Churiya range.

- **Movement:** the Siwalik rocks (Miocene-Pleistocene) are thrust southward over the Quaternary alluvium of the Terai.
- **Activity:** it is the youngest and most active of the Himalayan thrusts; it is active even today, with Holocene scarps and uplifted terraces.
- **Nature:** a series of splays, and in places blind thrusts.
- **Engineering importance:** earthquake hazard, surface rupture, ground deformation, slope instability at the Churiya foot, changes in river course and groundwater, and so it affects dams, barrages, bridges and roads of the Terai.

## Check yourself

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

1. Between which two zones does the MFT lie?
   A. Siwalik and Lesser Himalaya
   B. Terai and Siwalik
   C. Lesser and Higher Himalaya
   D. Higher Himalaya and Tethys
   Answer: B. The MFT/HFT is the southernmost thrust, separating the Siwalik in the north from the Terai plain in the south. (Key point: Location of MFT)

2. What is the movement along the MFT?
   A. Terai alluvium is thrust over the Siwalik
   B. Siwalik rocks are thrust southward over the Quaternary alluvium of the Terai
   C. Pure normal faulting with Siwalik dropping down
   D. Horizontal strike-slip only
   Answer: B. Older Siwalik rocks (Miocene-Pleistocene) are thrust southward over the young Terai alluvium. (Key point: Direction of movement)

3. What evidence shows the MFT is active today?
   A. Precambrian schist outcrops
   B. Holocene scarps and uplifted terraces
   C. Marine fossils in the Terai
   D. Granite intrusions
   Answer: B. It is the youngest and most active thrust, shown by Holocene scarps and uplifted terraces. (Key point: Activity)