Hello Tobias - You might find this page helpful: https://www.avo.alaska.edu/webicorders/ The seismic station records movement at the site - we can only tell the source of the movement by analyzing the data from several stations. The seismic stations themselves are quite sensitive - enough to record traces of larger worldwide earthquakes. We do not have any tiltmeters at AVO. Thank you, Cheryl -------- Tobias Smit wrote: The level of activity on the webicorder is interesting to follow from day to day. Could you explain the sensitivity of the instrument please? Is it surface motion or deeper down or lava movement? As well are there monitors to indicate rising(or lowering) of the surface? I think there are more instruments on the site how do you collect the data from them? Thank you I enjoy the way your web site informs. -- Cheryl Cameron Geologist, Alaska Volcano Observatory Alaska Division of Geological & Geophysical Surveys voice: 907-451-5012 fax: 907-451-5050