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Fredy Apaza

On 21 May 2016, two Differential Optical Absorption Spectroscopy (DOAS) instruments were used to measure the radiance of scattered solar radiation passing through the plume emitted from Sabancaya Volcano, Peru. Spectra were recorded in the ultraviolet (UV: 280 – 425 nm) and visible (Vis: 450 – 780 nm) wavelength ranges at 0.6 and 1.2 nm resolution, respectively. Two distinct experiments were performed using different measurement geometries. In the first experiment, two zenith-looking telescopes were mounted on a vehicle, each coupling scattered sunlight into one of the two DOAS spectrometers. The vehicle traversed beneath Sabancaya’s volcanic plume between 16:43 to 17:39 UTC collecting 2075 UV spectra and an equal...
After 3 years of mild gases emissions, the Ubinas volcano entered in a new eruptive phase on September 2nd, 2013. The MIROVA system (a space-based volcanic hot-spot detection system), allowed us to detect in near real time the thermal emissions associated with the eruption and provided early evidence of magma extrusion within the deep summit crater. By combining IR data with plume height, sulfur emissions, hot spring temperatures and seismic activity, we interpret the thermal output detected over Ubinas in terms of extrusion rates associated to the eruption. We suggest that the 2013–2014 eruptive crisis can be subdivided into three main phases: (i) shallow magma intrusion inside the edifice, (ii) extrusion and growing...
Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide...
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