Journal - Seismic model of central and eastern lesser Himalaya of Nepal

Seismic model of central and eastern lesser Himalaya of Nepal

Madhav Raj Pandey

Department of Mines and Geology, Lainchaur, Kathmandu, Nepal

Jour. Nep. Geol. Soc., Vol. 3, Number 1 & 2, 1985, 1-11


Abstract

The apparent velocity distribution of the local seisms of lesser Himalaya of central and Eastern Nepal allows to derive a three layered local seismic velocity model with first layer velocity of 5.6 Km/Sec. second layer of 6.5 Km/sec. and Moho discontinuity with 8.1 Km/sec. The first arrivals of different local phases of seismic waves are consistent with 20-23 Km thickness of the first layer and with crustal thickness of 55Km. The seismic events are confined to the first layer.

Local velocity model derived after the seismic event of 6 Oct 1981, origin time 19 hr 18 mn 17 sec, by modelling the first arrivals and PMP (Moho reflection) arrivals within the interval of distance 138-218 Km confirms the velocity model derived from apparent velocity distribution.

However, apparent velocity distribution of local seismic events occuring south of the line joining approximately Pokhara to Udayapur in plan does not seem to fit the theoretical distribution corresponding to the above three layered model with events within first layer. The apparent velocity of these events may be explained either (a) by the confinement of the focus of the events to the second layer or, (b) by the variation of the seismic velocity model with Moho depth at 35-40 Km. i.e. with a normal Indian peninsular crust thickness.

Member Login
NEWS AND EVENTS
  • Jul
    08

    Academic and professional development Sub Committee of the Nepal Geological Society and Nepal Geological Students’ Society in collaboration with Central Department of Geology has organized a training and interaction program entitled “Mining and Engineering Geology in field” on 23rd  Asadh 2075 at the conference hall of the Central Department of Geology, Kirtipur.

  • May
    21

    Nepal Geological Society has organized a press meeting on the memory of 2015 Gorkha Earthquake on 2075/1/12 at the conference hall of Department of Irrigation, Jawalakhel

Activities and Information

Activities of 17th and 18th Executive Committee
Nepal Geological Society
P.O.Box No. 231
Kathmandu, Nepal
FREEPHONE: +977-01-4437874
Email: info@ngs.org.np