Watching the wrecks: monitoring for oil slicks from sunken ships

Our Satellite Mapping experts use their SeaScope oil slick monitoring solution to respond to the environmental challenge posed by WWII shipwrecks.

Solomon Islands in the South Pacific are home to over 750,000 people, who live amidst a rich diversity of ecosystems, including lush mangrove forests and vibrant coral atolls. About 75% of the islanders sustain themselves through subsistence farming or fishing, which are heavily dependent on the natural environment. However, these delicate ecosystems, and the local way of life, are being jeopardized by an unexpected threat: oil leaks from sunken World War II warships.

After the Solomon Islands were invaded by Japan in 1942, many ships were lost in battles around the island of Guadalcanal as American and Australian forces aimed to retake the islands. Today, the waters north of Guadalcanal are known as the “Ironbottom Sound” to reflect the large number of shipwrecks in the region.

According to Geoffrey Thiemann, offshore technical lead for Viridien’s Satellite Mapping team: “With over 8,500 shipwrecks around the globe classified as ‘potentially polluting wrecks’ (PPWs), there is a growing understanding of the environmental hazard they pose and the need for governments, NGO’s and industry to begin remediation efforts. Computer modeling and investigations of WWII wrecks in-situ indicate that we’re now in a key decade where they are beginning to deteriorate significantly, with the risk of them starting to break apart or even collapse. This could potentially release any remaining oils as one large catastrophic event with devastating effects on the local environment and communities.”  

Viridien’s Satellite Mapping team is an active participant in Project Tangaroa, a global framework for the assessment, intervention and sharing of data relating to PPWs. For the last five years, it has also partnered with the Australian charity, Major Projects Foundation, to provide crucial satellite data interpretation to help locate PPWs. This collaboration has been instrumental in assessing the extent of oil leakage and devising strategies to mitigate the impact on the Solomon Islands' delicate ecosystems.

Geoffrey leads Viridien's efforts to support PPW investigations globally: “Viridien has a long history of using satellite imagery to map naturally occurring oil seepage in the maritime environment for commercial oil exploration purposes. As fixed-point sources on the sea floor, oil release from sunken wrecks generates oil slicks on the sea surface that act similarly to naturally occurring oil seeps that we usually map as part of our Global Offshore Seeps Database (GOSD). We also have a proactive pollution monitoring solution, called SeaScope, and we applied this to over 130 satellite images acquired over the Solomon Islands over the last 25 years.”

Viridien was able to document 377 oil slicks from potentially 23 shipwrecks. The pattern of oil leakage observed varied dramatically from vessel to vessel. Some, such as USS Atlanta off the coast of the capital city, Honiara, were observed leaking oil across most of the satellite imagery while other sites were only observed to be leaking oil in the days after major earthquakes in the region.

Dr Matt Carter, Research Director for the Major Projects Foundation, says: “Collaborating with Viridien has shown that it is no longer a question of if these wrecks are a threat, but instead to quantify this risk by assessing how much oil they are leaking and where it’s going. Significantly, the SeaScope results have enabled us to re-prioritise our database to focus on PPWs that are actively leaking and therefore require the most urgent attention.”

Previous Viridien collaboration with the Major Projects Foundation has helped to reveal the scale of oil release from PPWs at the Bikini Atoll nuclear test site, a UNESCO World Heritage Site. Viridien data also contributed to the discovery of the long lost wreck of the oil tanker Bloody Marsh off the US East Coast.

Geoffrey sees the Solomon Islands dataset as a key example of the big difference Viridien can make by offering its satellite mapping services as part of these pollution mitigation initiatives: “The impact of oil pollution to the Solomon Islands is of course critically important from an environmental perspective, but there is also the human imperative. The local people continue to be impacted by the remnants of a war they had little say over, and for which they by themselves have minimal means to remediate. Locating and monitoring these vessels is the first small step in redressing this complex issue. The window is also closing for naval authorities to locate these wrecks and bring closure for families who have lost loved ones during the Guadalcanal Campaign. I’m proud that Viridien can bring the benefits of our environmental monitoring solutions to serve the greater good of society and our planet.”

Learn more about Viridien's Oil Spill Detection & Monitoring services here.

Find out more about Viridien’s collaboration with Major Projects Foundation in the Solomon Islands featured in this Australian Broadcasting Corporation (ABC) News TV Report here. Read the related ABC article here.