The environmental effects of the eruption have been routinely monitored throughout the eruption. This has included the measurement of ambient sulphur dioxide (SO2) concentrations at ground level, the monitoring of fine dust particles in the air, and the measurement of the pH of rainwater.

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Measurements of the gas emissions from the volcano have been carried out throughout the eruption. These measurements have constituted an important input to the assessment of volcanic risk. Sulphur dioxide (SO2) and hydrogen chloride (HCl) are the species routinely monitored, primarily by remote sensing techniques.

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Recording and analysing volcanic earthquakes has been an important monitoring tool throughout the eruption of the Soufriere Hills Volcano. This Seismic Monitoring relies on a network of seismic stations, which has been continuously improved during the progress of the eruption. A network of three stations had been put in place by the Seismic Research Unit (currently, Seismic Research Centre) prior to the eruption. This was expanded during the first few weeks of the eruption with equipment and assistance from the USGS/VDAP program.

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Visual observations of the volcano are extremely important, both for monitoring escalating volcanic events as they develop, and also for tracking the growth of the lava dome over the long term. Several different techniques are used, including: visual observations and photography from the ground and from a helicopter; monitoring the activity with remote digital cameras; and topographic surveying of the lava dome by theodolite and photogrammetric methods in order to monitor its growth and estimate changes in volume over time, which in turn provide valuable information on rates of extrusion.