Detecting hydrothermal vents in volcanic lakes

Detecting hydrothermal vents in volcanic lakes
Steep crater wall of Ngozi volcano in the Poroto Ridge Forest Reserve, Tanzania. Credit: Egbert Jolie/GFZ

Geothermal manifestations at Earth's surface can be mapped and characterized by a variety of well-established exploration methods. However, mapping hydrothermal vents in aquatic environments is more challenging as conventional methods can no longer be applied. In fact, chemical composition of lake water may indicate inflow of fluids from a volcanic system, but it does not provide spatial information on the location of hydrothermal vents, their abundance and current state of activity.

Changes in the behaviour of may be indicative of changes in the volcanic system underneath, thus being a useful precursor for the next generation of early warning systems. Increased beneath volcanic lakes could also trigger increased gas input, in particular CO2, which could again result in catastrophic gas outbursts as reported from Lake Nyos or Lake Monoun in Cameroon. New exploration approaches will help improving site-specific risk assessment and monitoring concepts by taking a closer look at hydrothermal vents.

The study describes an integrated approach of bathymetry, thermal mapping of the lake floor, and gas emission measurements at the , which was tested successfully at Lake Ngozi in Tanzania. Multiple hydrothermal feed zones could be identified by hole-like structures and increased lake floor temperatures, in combination with increased CO2 emissions from the lake surface. The developed approach has the advantage that it does not require a complex technical setup, data can be obtained in-situ, and it is transferable to other volcanic lakes for mapping hydrothermal feed sources.

Further research activities at volcanic lakes and in shallow marine environments with hydrothermal activity (e.g., Iceland, Italy) are currently in preparation with partners from the Scientific Diving Centre (SDC) at the Technical University Bergakademie Freiberg, Germany, and the Marine & Freshwater Research Institute in Reykjavík, Iceland. This will also include research related to future offshore geothermal exploration.


Explore further

Shifting shorelines at Lake Tahoe caused by ancient lava dams

More information: Egbert Jolie, Detecting gas-rich hydrothermal vents in Ngozi Crater Lake using integrated exploration tools, Scientific Reports (2019). DOI: 10.1038/s41598-019-48576-5
Journal information: Scientific Reports

Citation: Detecting hydrothermal vents in volcanic lakes (2019, August 22) retrieved 19 September 2019 from https://phys.org/news/2019-08-hydrothermal-vents-volcanic-lakes.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
6 shares

Feedback to editors

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more