Bücher der Reihe IAVCEI Proceedings in Volcanology

It is probably true to say that the findings from Oldoinyo Lengai have dominated our ideas about carbonatites, in spite of the fact that the alkali rich, natrocarbonatitic lavas of Oldoinyo Lengai are markedly different from other carbonatites.

The Symposium was planned as a follow-up to a session at the 1984 Geo logical Society of America Annual Meeting in Reno, Nevada, which dealt with the emplacement of silicic lava domes. Recovering mineral resources found in lava flows and domes also requires an understanding of their emplacement.

The collection represents over half of the published abstracts of Symposium 4, together with three papers given at the Symposium, which lacked abstracts, and two which were part of Symposium 1 on pyroclastic flow deposits.

For many centuries people living on volcanoes have known that the outset of seismic activity is often a forerunner of a volcanic eruption. He identified the harmonic tremor which he indicated was a precursor of volcanic activity: "the characteristic feature of the ground mo tions preceding eruption is its continuity .