SEISMIC MONITORING OF THE UNSTABLE ROCK SLOPE SITE AT ÅKNES, NORWAY

The unstable rock slope at Aknes, Western Norway, has been identified as a potential threat for people and infrastructure in the inner Storfjord system. The unstable part has an estimated total volume between 30 and 40 million m3, and it is moving with a mean rate of about 4 cm/year, with some parts up to 15 cm/year. During the 2005 field campaign three seismic measurements/installations were made: 1) a refraction seismic experiment in the center of the slope, 2) a temporary installation of 10 seismic miniarrays for passive monitoring of seismic events and 3) a permanent installation of a small-scale seismic network for long-time monitoring with real-time data access.