Transcript
MURRAY FORD: In 2014, late 2014, the Hunga volcano erupted about 60km north of Tongatapu so we've been monitoring how that new island has been changing. Every couple of weeks a US geological survey satellite orbits above the volcano and I've been monitoring how it changes shape so I downloaded the latest satellite image for the area and noticed a really large plume of dirty water between Tongatapu and the Hunga volcano and contacted some vulcanologists that I know and asked them what was going on, whether they had heard reports of an eruption, and we managed to get some more recent satellite imagery and we could definitely see a vent there, which is putting out some volcanic debris into the water.
AMELIA LANGFORD: So, if you hadn't been looking at this, could this have gone undiscovered?
MF:I guess it depends on the persistence of the eruption. If it was just a one-off little pulse then maybe nobody would have noticed but if it was continuing, it's a large area of water, someone would have come across it eventually.
AL: So this was quite obvious - this plume was very obvious to the eye?
MF: Yes, we got a spectacular satellite image from the Landsat 8 satellite, which was largely cloud free, which is quite rare in the tropics, and you could see across 30 or 40 km of ocean, this big plume of dirty water - so in terms of that it was quite spectacular - to get such a cloud free view of the ocean.
AL: And was this in an area where any people might have seen it as well?
MF: Well, it's about 30 km from the mainland there, I guess it would be visible to local marine traffic - any boats passing through or fishing might notice some discolouration of the water but I'm not too sure whether it would be visible from land.
AL: So when you noticed this, were you quite excited?
MF: Yeah I was quite surprised to see it because I've been looking at this area for the last two years and hadn't seen anything like it. Yeah so right away it kind of piqued my curiosity and I got in touch with a vulcanologist here...in our department and he had a closer look at the imagery. Yeah, it was quite unusual and surprising to see.
