Temporal behavior and temperatures of Yasur volcano, Vanuatu from field remote sensing observations, May 2014

We documented eruption activity at three primary vents at Yasur volcano, Tanna Island, Vanuatu using portable instrumentation in the field over a period of 5 h on 21 May 2014, and acquired aerial images of the craters and vents on 22 May 2014. Although limited in duration, our observations of eruption intervals, durations, temperatures, and speeds of ejected material illustrate the characteristics of the activity at the time at each of the primary vents, providing a useful snapshot of eruption behavior and revealing continued variability at Yasur in comparison to other observation campaigns. Hand-held, high-resolution, near-infrared observations of one of the vents gave peak temperatures of 850 °C to 930 °C for ejected clasts, with a maximum temperature of 1033 °C. These temperatures are significantly higher than previous measurements because exposed lavas could be resolved at timescales less than a second. Our aerial near-infrared images allowed us to estimate the combined area of the active vents within the crater to be ~ 150 m2, and comparison to MODIS radiance measurements in the same time frame yields temperatures, averaged over the combined vent area, of 530-730 °C. In the context of previous observations at Yasur, the activity in May 2014 exhibited lower overall intensity, as well as differences in the nature of the eruptions at the various vents, providing insight regarding the temporal variability of Yasur's activity.