Dynamics of the Ocean Floor

Volcano Monitoring Group

Figure 1: Remote Sensing techniques used for volcano monitoring

Figure 2: Stationary Mini-DOAS at Villarrica volcano, South-Central Chile

Responsible: Dr. Thor H. Hansteen

Introduction

The volcano monitoring group focuses on near-real time evaluation of changes in SO2 fluxes from active volcanoes, which is used to assess the activity state of each volcano. In combination with other data types like seismic signals, ground deformation, and thermal anomalies, volcanic gas monitoring is used as an indicator of ongoing magmatic activity and thus represents an important tool for volcanic hazard mitigation. 

 

Gas flux measurements of active volcanoes

Volcanic gases contain SO2, which can be quantified using ultraviolet (UV) light spectroscopy. We utilize ground-based Scanning Mini-DOAS (miniature – Differential Optical Absorption Spectrometer) systems, which were developed during the EU-funded project NOVAC, in which we were partners. The instruments use scattered sunlight as a light source, and can measure both areal SO2 concentrations and fluxes. A time-resolution of several minutes per acquisition enables correlations with e.g. seismic data, thus significantly extending the information available for real-time risk assessment and research at the volcano.

We are operating several arrays of scanning Mini-DOAS instruments with a special focus on Chilean volcanoes (SFB574(at)geomar.de). Mobile versions of the instruments can be used as part of a volcanic task force effort (EXUPÉRY VFRSBOEING).

  

Additional techniques used for volcano monitoring

We use additional multispectral techniques for remote measurements of volcano behavior. Gas flux monitoring exploits absorption bands of gases in the ultraviolet/visible and infrared (IR) regions of the electromagnetic spectrum. Satellite data provided by various sources can be used to estimate the composition of volcanic plumes and to detect thermal anomalies at volcanoes.