The Nanga Parbat-Haramosh monitoring network.

If the Himalayas are a land of extremes from the topographical, geophysical and geological point of view (Windley, 1984, 1988), the Karakorum is a land of superlatives, having the highest concentration of mountains over 8000 metres, having the longest glaciers outside of the poles, being the source of one of the longest rivers. From the geophysical point of view it contains the largest gravity anomalies (Poretti et al., 1983) and thickness of the earth crust (75 km) (Finetti et al., 1978, 1983) and the highest values of deflection of the vertical. It also contains the highest relief (4000 metres from the Indus plains to the summit of Nanga Parbat). It seems also that this area is subject to the highest uplift. This has been mentioned by many authors who derived it through indirect methods, but had not yet been confirmed by accurate direct observations. Lewis Owen reports 0.7 mm/y using fission-track methods (Owen, 1981). Higher values (2 mm/y) are inferred by several researchers (Zeitler 1985, Gorniz and Seeber 1981; Lyon-Caen and Molnar 1983; Ferguson, 1985 and again Owen, 1989). Finally an average value of 6-10 mm/y was in the hypothesis of Zeitler et al. 1985 including uplift and erosion. These values were calculated through indirect methods, but no tentative was made to calculate the uplift of the Nanga Parbat - Haramosh massif through direct surveys. The present study shows the preliminary results of a first survey consequent to the installation of a GNSS network including three permanent GNSS stations between Islamabad and the Northern Areas of Pakistan and four points located on the Nanga Parbat – Haramosh massif. These points will be surveyed once a year during the next 6 years and will provide a fair record of their movements, both horizontal and vertical, with respect to the surrounding areas. During the processing of the surveyed data, the observations of the International GPS Network Kit3 situated at in Uzbekistan will be taken into account. Another problem tackled by this research is the determination of the stability of the two banks of the Indus river in the area where the Diamer Basha dam is being built. The repeated measurements, before, during and after the construction of the dam will be an important index of the change in the geophysical parameters produced by the dam and the related lake. GPS and classical distance measurements will be performed on a network of 6 points located on both sides of the river.