Possible effect of aspect ratios of magma chambers on eruption frequency

The eruption frequency of volcanoes, even within the same region, is highly variable. In volcanic regions associated with stress fields that are essentially uniform (but anisotropic), as at plate boundaries, the explanation for the range in eruption frequency must lie within the volcanic systems themselves. I propose that differences in eruption frequency of volcanoes within the same volcanic region may be due to different aspect ratios of the magma chambers that feed the volcanoes. For a magma chamber of elliptical cross section with half-height h and half-width w, the higher the h/w ratio the more frequent will be the eruptions.