Heat and mass flux measurements using Landsat images from the 2000–2004 period, Lascar volcano, northern Chile

Abstract

A qualitative and quantitative analysis of 13 Landsat TM and ETM+ images of Lascar volcano for the 2000–2004 period was performed by applying the three bands and three components method to determine heat and mass flux and understand the magma circulation process in a passive degassing volcano related to permanent fumarolic activity. The behavior and evolution of spectral radiance during the study period suggest that prior to low-to-moderate magnitude eruptions these values reach their localized temporal minimum levels, corresponding to 1.9–4.38mW/cm2srμm in July 2000 and 4.38–7.11mW/cm2srμm in December 2003 eruptions, respectively. Similar behavior is observed for anomaly area, heat and mass fluxes. During the 2000–2004 period the heat flux was estimated to vary from 75.46 and 10,527MW, while mass flux ranged between 131 and 18,469kgs−1. A magma circulation model is proposed to explain these variations, where the thermal anomaly is related to the presence of a fumarolic field and fluids movement from a magma chamber located at ~10–17km depth.