A rapid deployment instrument network for temporarily monitoring volcanic SO2 emissions - a case study from Telica volcano

Volcanic gas emissions play a crucial role in describing geophysical processes; hence, measurements of magmatic gases such as SO2 can be used as tracers prior to and during volcanic crises. Different measurement techniques based on optical spectroscopy have provided valuable information when assessing volcanic crises. This paper describes the design and implementation of a network of spectroscopic instruments based on differential optical absorption spectroscopy (DOAS) for remote sensing of volcanic SO2 emissions, which is robust, portable and can be deployed in relatively short time. The setup allows the processing of raw data in situ even in remote areas with limited accessibility, and delivers pre-processed data to end users in near real time, even during periods of volcanic crisis, via a satellite link. In addition, the hardware can be used to conduct short-term studies of volcanic plumes in remote areas. We describe here tests of the network at Telica, an active volcano located in western Nicaragua, during three different measurement periods, including an eruptive crisis. The tests produced what is so far the largest data set of continuous SO2 flux measurements at this volcano. The measurements show that, during the period 2010-2013, the flux averages approximately 100 tons per day (t day(-1)).