Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

The continued compression between Indian and Asian continental plates which ultimately led to the collision of the two, is regarded as the most likely phenomenon responsible for the emergence of Himalaya. The stress build up across the strike of the orogen produced regional north-south compressional structures including two major tectonic boundaries/ discontinuities namely the Main Central Thrust (MCT) and the Main Boundary Thrust (MBT). In the mountain building process the seismic outbursts (earthquakes) and tectonic adjustments are indicators of strain release. In the last century, this region has experienced four major earthquakes measuring above 8 in the Richter Scale besides a number of moderate magnitude earthquakes and is still reeling under recurring seismic tremors. In Uttaranchal these activities are much pronounced as the entire state belongs to seismic zone IV and V with a number of earthquakes in the past. The most recent Uttarkashi Earthquake (1991) and Chamoli Earthquake (2001) were of the magnitude 6.6 and 6.8 respectively. The landslides triggered by the earthquakes are classified as seismogenic landslides. These seismogenic landslides are otherwise known as dynamic landslides, which can be further, divided into two main classes such as (i) seismo -gravitational and (ii) seismotectonic. Himalaya, being geodynamically very active parts of the lithosphere, tectonic and neotectonic activities are well explained in the earthquake prone zones. The major tectonic boundaries like the MCT, MBT and HFF and many smaller intra boundary thrusts/ faults are specifically vulnerable concerning seismogenic landslides more specially the Uttaranchal region. Majority of landslides along the MCT zone and adjoining Higher and Lesser Himalaya are of seismogenic class while seismotectonic landslides are concentrated more in the sub-Himalayan zone. The present communication mainly focuses on the relationship between seismicity and landslides in Himalayan region. The attention will be drawn mainly towards seismogenic landslide activities with a special reference to Uttaranchal Himalayan region.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Seismogenic Landslides in Himalaya With Special Reference to Uttaranchal

New York, New York

The continued compression between Indian and Asian continental plates which ultimately led to the collision of the two, is regarded as the most likely phenomenon responsible for the emergence of Himalaya. The stress build up across the strike of the orogen produced regional north-south compressional structures including two major tectonic boundaries/ discontinuities namely the Main Central Thrust (MCT) and the Main Boundary Thrust (MBT). In the mountain building process the seismic outbursts (earthquakes) and tectonic adjustments are indicators of strain release. In the last century, this region has experienced four major earthquakes measuring above 8 in the Richter Scale besides a number of moderate magnitude earthquakes and is still reeling under recurring seismic tremors. In Uttaranchal these activities are much pronounced as the entire state belongs to seismic zone IV and V with a number of earthquakes in the past. The most recent Uttarkashi Earthquake (1991) and Chamoli Earthquake (2001) were of the magnitude 6.6 and 6.8 respectively. The landslides triggered by the earthquakes are classified as seismogenic landslides. These seismogenic landslides are otherwise known as dynamic landslides, which can be further, divided into two main classes such as (i) seismo -gravitational and (ii) seismotectonic. Himalaya, being geodynamically very active parts of the lithosphere, tectonic and neotectonic activities are well explained in the earthquake prone zones. The major tectonic boundaries like the MCT, MBT and HFF and many smaller intra boundary thrusts/ faults are specifically vulnerable concerning seismogenic landslides more specially the Uttaranchal region. Majority of landslides along the MCT zone and adjoining Higher and Lesser Himalaya are of seismogenic class while seismotectonic landslides are concentrated more in the sub-Himalayan zone. The present communication mainly focuses on the relationship between seismicity and landslides in Himalayan region. The attention will be drawn mainly towards seismogenic landslide activities with a special reference to Uttaranchal Himalayan region.