International Journal of Economic and Environmental Geology
Not a member yet
352 research outputs found
Sort by
Pre and Post Earthquake Seismo-Tectonic Scenario of Hazara-Kashmir Terrain of Pakistan
Full text link The Hazarn-Kashmir(HK) terrain is located on the northwestern margin of the Lesser Himalaya. The Hazara Kashmir Syntaxis (HKS) is one of the bold tectonic scars, which physically seperate this terrain from rest of the Himalaya.The major tectonic features sculpturing this terrain in the shape of folds and faults are: Hazara-Kasmir Syntaxis (HKS), Main Mantle Thrust (MMT), Main BoundaryThust (MBT), Panjal Thrust (PT), Hazara Thrust (HT) and Indus Valley Faults (IVF). All these mega-structures are the abode of variablc seismicity and generate earthquakes of low to moderate magnitudes. Among them, thc MMT, MBT, PT and the IVF have hazardous seismic history. The earthquake of October, 8, 2005 of magnitude 7.6 with its epicenter, located south of Balakot is linked with one of these faults, the MBT, Which traverses the eastern and western flanks of the HKS.The deep mega-crustal deformations beneath the Hazara-Kashmir terrain monitored through seismicity arc: Indus-Kohistan Seismic Zone (IKSZ), Hazara Lower Scismic Zone (HLSZ) and Tarbela Seismic Zone (TSZ). The epicenter of earthquakes generally lies between 10-60 km depth in the seismic zonc of the mega-crustal deformations in the HK terrain. The earthquakes generated at this depth are categorized as shallow and usually more hazardous. The successive events in the seismic profle betwcen years 2003-2005 were a reliable precursor to predict accumulation of energy, which ultimately caused the earthquake on October 8, 2005
Moho Discontinuity Depth Estimates for the Cameroon Volcanic Line from Gravity Data
Full text linkIn this work, the Moho depth in a part of the Cameroon Volcanic Line (CVL) between the latitudes 3°30' to 6°33' N and the longitudes 8°50' to 11°27' E has been estimated covering two distinct regions: the Mount Cameroon and the Bamenda by the use of polynomial separation of gravity data and spectral analysis along two profiles. The Moho is uplined in the Mount Cameroon region, where the crust is thinned to about 24 km. In the Bamenda region, the crustal thickness is found to be normal at about 31 km. The high positive gravity anomalies of up to 100 m Gal observed in this area indicate the thinning of the crust in the Mount Cameroon region. Seismic and gravity data indicate a custal thickness of 30-34 km along the continental parts ofthe Cameroon Volcanic Line, except in the Adamawa plateau, where the crust's thickness ranges between 20-23 km. The crustal thickness of about 31 km in the Bamenda region is an evidence of perfect isostatic compensation, which suggests a deep seated source for the negative anomnaly, resulting in a general asthenospheric uplift along the Camcroon Volcanic Line