Volcano

Volcano-Stress

An Emmy Noether Junior Research Group

Dr. T. R. Walter
Dipl. Eng. A. Manconi
Dipl. Geol. J. Ruch
Dipl. Geol. N. LeCorvec

Project duration: 2005-

According to traditional ideas, the growth and collapse of volcanoes is controlled by deep seated processes. However, it appears that also very shallow or even external mechanisms may govern the magmatic and structural evolution of volcanoes. These mechanisms can be better understood by analysing the state of stress and stress field changes within the volcano edifice and its surrounding

Evidences are increasing that already small changes of the stress field may significantly affect magmatic systems and fault zones. Albeit a vital academic and applied importance, the processes of stress changes occurring during earthquakes, intrusions and topographic disturbances, as well as the associated mechanic and dynamic interrelations are not understood. The elaboration of communicating processes is the central aim of the Junior Research Group. Causes and effects to be investigated focus on gravity, earthquakes and intrusions: (a) How does the gravitational load develop within a growing volcano edifice in consideration of constructive and destructive episodes, i.e. loading and unloading? (b) What is the effect of stress transfer due to (tectonic) earthquakes? (c) How do intrusions and flank instability interact and control the dislocation type.

The methods comprise structural field work, geodetic deformation measurements utilizing the satellite radar interferometry, as well as extensive modelling. The central aim of research efforts at case studies is to characterize the state of stress within an active volcano edifice, and herewith to identify and quantify mechanisms of deformation and volcano-tectonic interactions. 

Fig. 1: The 1996 synchronous eruption of the adjacent volcanoes Karymsky and Akademia Nauk, Kamchatka, initiated shortly after a tectonic earthquake. Did the earthquake affect the crustal stress field and trigger the eruptions?

 

Fig. 2: Causes and effects of gravitational loading and stress changes, and complexity of a volcano edifice. Loading controls gravitational spreading, as well as magma emplacement and flank instability. Due to intrusions and earthquakes a temporal and spatial multifaceted redistribution of the stress field occurs within the mechanically heterogeneous medium of the volcano edifice.