Geochemical monitoring at active volcanoes comprises of the following:
Monitoring of this type at Volcán de Colima has produced excellent results. The details of the methodology with updated results are presented elsewhere. It has been established that a clear link exists between the concentration of boron in spring waters and activity. When there is no activity, the boron level remains below the detection limits. Peaks have been observed some 2-3 months prior to episodes of effusive activity. The ground water below the lower slopes includes a component of deep fluids. Boron is a volatile species present in magma and the concentration in the deep fluids increases as a result of a uprising magma body.
A study of diffuse degassing may observe temporal variations in the CO2 concentration in the soil gas or the flux leaving the soil surface. After removing any meteorological effect, variations could be related to the uprising of a magma body. Radon can act as a useful indicator gas since it is relatively easy to measure. Track etch detectors have been tested in one location on the SW flank of Volcán de Colima to record the integrated Rn concentration. These were retrieved on a monthly basis. At a second location, a solid-state Rn detector is constantly measuring the concentration. One further detector will be installed during 2007. Additionally, monthly readings of CO2 flux have been taken at several locations to observe if any correlation exists with volcanic activity.
Juan Carlos sampling a fumarole during 2001
Sampling spring water from La Lumbre
COSPEC (COrrelation SPECtrometer) measuring SO2 flux