Seismic interpretation of Hilat-Al-Sad landslide, Muscat, Sultanate of Oman

Recent landslides of Pakistan (2005), Boulivia and Indonesia (April, 2003) caused huge losses of lives and property. Such threatening landslides are widely distributed in the world and in Oman too. Several have occurred in the last two decades due to slope failure and/or rock cutting for socio-economic purposes. Hilat Al-Sad landslide is one example of Al-Wattayah(Muscat) landslides which spread panic in 1996. It was activated just after the completion of a rock cut. The sliding raised a question whether it happened due to rock cutting activity or due to regional stresses. For searching the evidence, shallow seismic refraction investigations were carried out in this structurally folded and faulted rocks of varied lithology and ages, using 24-channels seismic recorder and the hammer as energy source. The orthogonal seismic spreads revealed the existence of two perpendicular faults within 20 meters depth. But sliding was found to be unrelated to the faults; it appears to have occurred due to toe failure on a weaker plane developed recently or previously.