Of Pahoa, pahoehoe and people

Hilo

Senior scientists often (used to?) say that, when talking to their fellow citizens about matters scientific, the public need facts, certainties, and anything to do with uncertainty should be kept well away from them. More nuanced takes on science communication aver that what people really need to know about is how science really works, and that involves notions that scientists are people just like them, with their various falibilities, their doubts and their uncertainties.

I’ve felt for a long time that genuine science communication had to adopt a much more intermediate and pragmatic approach: citizens do look to scientists to give them facts and reliable information – otherwise what is the point of paying them a salary, often from the public purse; but they can cope with the ideas of uncertainty and the limits to existing knowledge and what is knowable without going into a blind panic. Until now, however, I had not really seen it work in practice quite like that.

Whilst the rest of the USA is preparing for Thanksgiving Day (Thursday, November 26, this year), the little town of Pahoa on the Big Island of Hawai’i is wondering just how many Thanksgivings they have to come – including this one.

Hawai’i is an active volcano, and the Pu’u O’O vent on the eastern flank of Mauna Loa has been steadily pouring lava downslope into the sea for decades. Normally the lava flows east or south-east. But on June 27 this year, the flow turned dangerously north-eastward, toward Pahoa. And it has been heading for the town ever since.

The lava approaching Pahoa is known as pahoehoe. It is a smooth, sticky lava that generally flows slowly downslope. This is in contrast with the explosive pyroclastic flows of the sort that engulfed Pompeii in 79AD, which move so fast no one has a chance to get out of the way.

The main flow cut through Cemetery Road on the outskirts of town some time ago, burned down its first house earlier this month, surrounded the $3 million-plus, state-of-the-art, Waste Transfer Station, and is now stalled just short of the main road through the town centre. Given the relentless approach of the lava, one might imagine the townspeople to be giving a pretty good impression of Corporal Jones and Private Frazer in “Dad’s Army”. No.

Local citizens have been getting together with scientists from the United States Geological Survey (USGS) on a weekly basis since August 24 this year. I went to the meeting on November 20 along with some 300 Pahoa inhabitants – about half of the adult population. The update from the USGS started with a quiz about the three factors controlling lava flow – what is happening at the summit of Pu’u O’o, what is happening with the lava tube that carries the lava down towards the town, and the nature of the terrain over which the lava finally pours when it emerges from the tube.

November 20’s update was that although Pu’u O’o was producing about one third more lava than it had been two weeks ago, a break-out near the crater summit had robbed the lava tube of its lava and led to surface flows far upslope from the town. The terrain there was tending to take that lava away from Pahoa. But – and here the USGS were very clear – the future was highly unpredictable. Would the lava tube refill, leading to flows resuming towards the town? Not sure. If so, how soon would the flow nearest the town restart? Not sure.

The approach of the local USGS scientists as well as public bodies such as the health and rescue services, the National Guard, and the Mayor’s office has been to let local citizens know what they know and tell them what they do not know. Locals are also encouraged to use their own eyes, ears and – given the various smells of sulphur dioxide and burning that accompany the lava wherever it goes – noses. Representatives of the various relief bodies mix freely with the Pahoans to discuss, listen to eye-witness accounts and answer the questions that their expertise is best suited to answer.

Schoolchildren who have been forced to move school because of the poor air quality are to be among the first to be taken to see the main flow itself, when the situation is deemed safe enough to do so. That way they can appreciate at first hand why their island home makes so many demands on those who live there.

The result is that the people are generally well informed and, at the same time, feel involved with, and even in control of, their situation, insofar as anyone living with an active volcano can feel in control. Any Corporal Joneses have learned that “don’t panic” means just that. Any Private Frazers have been reassured that, whilst we are all ultimately “doomed, doomed”, it is “just not quite yet”.

In the meantime, Pahoa residents are also preparing for Thanksgiving. As Mayor Billy Kenoi said: “We just want some normalcy here.”