Tristan : Administrator Speaks About Recent Seismic Activity
Submitted by Tristan Times (Juanita Brock) 15.09.2004 (Current Article)
This interview was conducted by Alex Kirby of the BBC World Service for "Calling the Falklands."
Photo (c) J. Brock (SARTMA-TdC)
TRISTAN’S ADMINISTRATOR SPEAKS ABOUT RECENT SEISMIC ACTIVITY NEAR THE ISLAND
A Report for BBC World Service “Calling the Falklands” by Alex Kirby (AK) 14/09/04
Besides seismic equipment on Tristan, there are several stations like this dotted around the Island.
In the South Atlantic there’s another Island facing an uncertain future because of natural forces – Tristan da Cunha. For six weeks now, it’s been swayed by earth tremors. Obviously, for the 279 inhabitants of the Island, any major geological activity could have a disastrous affect for their community. Dr. Vicky Hards a British Geological Survey scientist, arrived on Tristan just last Friday to monitor the activity. So far, her initial findings sound reassuring. Mike Hentley (MH) is the Island’s Administrator and he told me that the tremors have prompted some of the older residents to recall the volcanic eruption of 1961, which caused a mass evacuation.
MH: Some of those whose memories that do go back that far said the original volcanic activity started exactly like this. So, initially, there was a bit of concern. But I think the initial conclusions that BGS are having, that there is continuing activity but it appears at this stage to be offshore, whereas 40 odd years ago it was very definitely under the Island itself.
AK: Well, that may be reassuring but presumably on Tristan you always have to be on the alert for seismic activity because there is something of a South Atlantic hot spot.
MH: That’s exactly it. I am not an expert myself, Alex, but I understand that we are on the South Atlantic Ridge and that goes all the way up to Iceland. Of course, all of the Islands that pop up above sea-level are the result of volcanic activity. And, there is something of a hot-spot in the area. Occasionally we do feel it. There is evidence that Tristan is a relatively young Island. It’s just a baby in geological terms, as I understand it. And, there is evidence that volcanoes dotted around the Island show that something occasionally pushes its way up to the surface.
AK: It may be reassuring to think the activity this time is offshore rather than underneath you but “offshore” is a fairly elastic term, isn’t it? Once there is seismic activity, it can spread very rapidly over very large areas, so “offshore” isn’t really that reassuring, isn’t it?
MH: Certainly, we shouldn’t be complacent. We are also in a better position than we were 40 years ago because we now have seismic management equipment actually installed on the Island. And, as you say, if things get nearer rather than further away, then we hope we can have some good warning. The main concern is that the shaking could produce rock falls and this sort of thing. Because, we have beautiful scenery here – I am looking out of my window at huge cliffs going up about 2,000 feet. Obviously, if they started shaking, we could have land-slip and I could have a rock come in and land on my head. I don’t think I’d enjoy that.
AK: I’m sure you wouldn’t. I have heard that there have been floating rocks around the Island. That must be fairly disconcerting, Isn’t it?
MH: The whole thing is fascinating. They are something described as pumice – a very crumbly, light grey stone. Now, our fishermen went out on the 2nd of August and found some fairly huge lumps of this, up to 10 or 12 kg floating on the surface to the south/west of the Island. As the experts suggest, there is some activity that brought this up.
AK: I think if I were there with you, Mike, I should be wearing my hard hat indoors as well as out. Thank you very much, indeed. I hope it doesn’t come to an evacuation.
MH: That’s very kind of you. Thanks very much indeed.
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