A multimodal and multitemporal assessment of mud volcanism in Azerbaijan by drone and remote sensing

Understanding the impact of mud volcanism and associated hydrocarbon flow towards the surface is critical for safety of drinking water, agriculture and during hydrocarbons exploration. These natural phenomena are abundant in Azerbaijan as well as in other countries. Newest developments in drone-based analytical and mapping technologies, as well as freely available high-resolution satellite data, open new possibilities. The aim of our project is to map and evaluate migration pathways of fluids from the regional scale down to one mud volcano, and to evaluate the environmental impact of natural seepages of hydrocarbons. The WNW-trending Greater Caucasus fold- and thrust-belt is characterized by S-SSW verging folds and associated thrusts (e.g. Devlin et al., 1999; Saintot et al., 2006). Horizontal tectonic stress is assumed to be oriented c. 30° with c. 10 mm/year movement velocity (Bonini and Mazzini, 2010). Muds and associated fluids migrate from overpressured shales in up to 5 km depth along faults and fracture networks to the surface and generate constant small seeps and degassing of methane (Guliyev, 2006). We conducted lineament mapping based on ASTER-data and studied their dilation and slip tendency with 3DStress-software. This fault data is complimented by field measurements of faults and fractures, as well as Structure from motion on outcrops. Additionally, high resolution mapping of mud volcanoes and associated fluid flow by means of drone-based photogrammetry and drone-based methane detection were carried out. Fault orientations along the Greater Caucasus show a majority of faults striking WNW, paralleling the mountain range. Stress analysis of faults show medium to high dilation tendencies for northerly striking faults subparalleling the main horizontal stress and are available for fluid flow. By analysis of mud volcano and fault location we observe that over 50% of mud volcanoes are located over or close to fault intersections. In our four study areas, fractures strike mainly N-S and W-E in the southeastern part, and NNE-SSW and WNW-ESE in the northwestern part. Drone-based methane detection works at max. flight altitudes of 15 m and a max. speed of 2 m/s. Macro- and mini-seepages away from the main gryphons reveal concentrations of up to 10 ppm per meter air column around mud volcanoes. Digital elevation models and orthophotos of one studied mud volcano before and after one eruption reveal structural details and eruption volume.