Mirza Shahid Baig

Lithological and Structural Control of Hattian Bala Rock Avalanche Triggered by the Kashmir Earthquake 2005, Sub-Himalayas, Northern Pakistan

The Kashmir earthquake 2005 (magnitude MW 7.6) triggered thousands of mass movements in northern Pakistan. These mass movements were mainly rock falls, debris falls, rockslides and rock avalanches. The mass movements vary in size from a few hundred cubic meters up to about 100 million cubic meters estimated for the Hattian Bala rock avalanche, the biggest one associated with this earthquake. This mass movement, which moved in southeastern direction, created two natural dams on the valley bottom and blocked the water ways of the Karli and Tung tributaries of the Jhelum River. Topographic, lithologic and structural information were used to investigate the Hattian Bala rock avalanche. Geotechnical and structural maps were prepared to understand relationship between geology and structure of Hattian Bala rock avalanche. The geometry and failure mode of this rock avalanche are controlled by southeast plunging synclinal structures, lithology, a bedding parallel slip surface and a pre-existing old rockslide. The structural map shows that the mass movement failure was due to Danna and Dandbeh synclinal structures plunging southeast on the hanging wall block of the reactivated Muzaffarabad fault. The slip surface of the mass movement followed the bedding planes along mudstone, claystone and sandstone surfaces. The mass movement perfectly followed the pre-existing synclinal morphology of the Danna and Dandbeh synclines.

Radon Levels in Dwellings of New Mirpur Azad Kashmir, Sub-Himalayas, Pakistan:

Radon concentrations were measured in kucha, semi-kucha and pucka houses located on the sedimentary rocks of Early Pleistocene-Pliocene Soan Formation, Pleistocene Mirpur conglomerate and recent deposits. The radon concentration was measured using CN 85 nuclear tracks etch detectors in box type dosimeters installed in the bedrooms and kitchens of the houses. It was found to vary from 14 ± 7 Bqm-3 to 258 ± 28 Bqm-3 with an average of 105 ± 17 Bqm-3. The average radon concentration in the kucha, semi-kucha and pucka houses was 78 ± 15 Bqm-3, 108 ± 18 Bqm-3 and 108± 18 Bqm -3 respectively. The increase in radon concentration from kucha to pucka houses was attributed to the type of house, differing humidity related to the Mangla Dam, temperature, bed rock geology, structures (joints, fractures and faults), aggregates and uranium-bearing sand. This study shows that the average radon level is within the accepted safe health limit (200 Bqm -3) for the inhabitants of New Mirpur Azad Kashmir, Pakistan.

Large scale mass movements triggered by the Kashmir earthquake 2005, Pakistan

The SPOT image analysis in Muzaffarabad Azad Kashmir, northwest Himalayas, Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffarabad Fault. The Neelidandi and Langarpura rock falls have been identified as two major reactivated mass movements with an estimated volume of 3.1 × 106 m3 and 5.76 × 106 m3, respectively. The Neelidandi and Langarpura mass movements were initiated during earthquake in the direction of northwest-southeast extension and northeast-southwest directed thrusting, respectively. The Neelidandi rock fall occurred in sheared cherty dolomites and limestones of the Cambrian Muzaffarabad Formation, whereas the Langarpura rock fall occurred in alternating clays, shales, claystones, siltstones and sandstones of the Miocene Murree Formation. These rock units along the fault are highly fractured and jointed. The geotechnical maps and geological longitudinal profiles show the relationship between the geometrical characteristics and mechanism of these mass movements. Their characteristics were analyzed according to the role of topographic, seismic, geological and tectonic factors. The steep topography, sheared rocks, lithology, coseismic uplift and strong ground shaking of the hanging wall block along Muzaffarabad Fault facilitated the gravity collapse of these mass movements.

Structure and stratigraphy of Rumbli and Panjar areas of Kashmir and Pakistan with the aid of GIS

The project area lies in the southern part of the Hazara Kashmir syntaxis. The Hazara Kashmir syntaxis is an antiformal structure. The project area includes Rumbli, Namb, Chatrora, Chachan, Panjar, Barathian and Utrinna areas of Rawalpindi and Sudhnoti districts. The southeastern limb of the Hazara Kashmir syntaxis is imbricated along Punjal thrust, Main Boundary thrust and Riasi fault. The Jhelum fault truncates the western limb of Hazara Kashmir syntaxis. The core of syntaxis comprises of Himalayan molasse deposits. These molasse deposits represent the part of cover sequence of Indian plate. These Himalayan molasse deposits include the Early to Middle Miocene Kamlial Formation, Middle to Late Miocene Chinji Formation, Late Miocene Nagri Formation and Late Miocene Dhok Pathan Formation. The area is highly deformed resulting folds and faults. The major folds in the project area are the Panjar anticline, Barathian syncline, Barathian anticline, Rumbli anticline, Chatrora antiformal syncline and Namb syncline. The folds are either northwest-southeast trending or southwestnortheast trending. The folds are asymmetric, open, and gentle and close in nature. The folds are southwest, northeast or southeast vergent. The Jhelum fault truncates the northeast and northwest trending structures. The folds and faults are the result of northeastsouthwest or northwest-southeast Himalayan compression.