Figure 7

Plots of tiltmeter data from the electronic tilt station, Retu, located on the NW flank of Tungurahua at 4000 meters elevation. The pattern of a pronounced inflationary trend than followed by a strong downgoing “deflationary” pattern of tilt on the radial axis has been a guide for IGEPN scientists to be alert for onset of Vulcanian eruptions. Dates in boxes are onset of main Vulcanian eruptions.