A spatial-temporal approach to analyzing diffuse vent heat flow patterns in the ASHES hydrothermal field of the Axial Volcano

Abstract:

The Diffuse Vent Fluid 3-D Temperature Array (TMPSF) measures temperature using a 24 thermistor triangular spatial grid within the ASHES vent field in the Axial Volcano caldera. We conducted an analysis of temperature data from two separate deployments from 2014 through the 2015 eruption and from 2017 to the present day. Analysis of temperature anomalies in the first deployment reveals the presence of two predominant tidal frequencies (with periods of 11-13 hours and 23-26 hours) and a strong third lower frequency peak. The two tidal frequencies decreased in strength during the eruption remaining low into June, with thermistors experiencing higher temperatures showing a weaker response to the eruption-related seismological and volcanic fluctuations. Exploration of thermistor-to-thermistor correlations reveals that physically adjacent thermistor readings correlate strongly during the second deployment (in an area of high vent activity) but less so during the first deployment. (Figure 1) This suggests greater mixing, despite less uniform temperature readings overall, in the current slow-inflation regime compared to the pre-eruption state. This paper evaluates the TMPSF’s ability to model 3-D heat flow, and applies collected spatial and temporal patterns to draw conclusions about vent reactions to seismic and volcanic activity.