While the others continued with repairs and tidying of the ShakenVacc, Will and Taeva looked at a map and discussed placing of the seismic charges. Will looked on nervously as Taeva fiddled with the timers and electronics of the devices.
The survey would take a full day of their time, and would involve emplacing a series of seismic charges and detonating them. The charges were on board the ship, and most of the morning was spent ferrying them to various points along the shore.
In addition they needed to place a number of ground sensor units all over the crater and in some of the lava tubes running off it. Charges would need to be set off in some of the tubes
as well. The effects of the charge detonations could then be used by the (now functioning) scout ship’s computer to create a 3D model of the volcano. When matched up with readings taken by more sophisticated sensors like the vessel’s high-penetration densitometer, this would allow the computer to predict if and when an eruption was likely. Other indicators included measurements of the lake temperature and samples of the gas mix around the crater area, and Will happily set off doing these while Taeva placed the charges.
As Taeva blew the last of the charges she headed back to the boat; in the distance she could see Will still taking water samples from around the edge of the lake. And then the ground started to shake.
The tremors were not particularly violent, but it was still going on ten minutes later as Taeva reached the dinghy. On the island she could see Grim and the others racing around in panic.
“Will, what the Fuck is happening?” screamed Taeva. Will grinned.
“Oh don’t worry, " shouted WIll, It’s likely nothing at all to do with the charges. These things happen on volcanos; we’d best wait for the computer analysis."
Oddly enough Taeva didn’t find that reassuring.
As they rowed back across Taeva noticed something else.
“Will, the lake level is dropping” she said. Looking over the side they could see bubbles arising from one corner of the lake, and also venting of smoke from the southeast side of the mountain. As they disembarked the tremors subsided, and the bubbling ceased.
By the time the ship’s computer had analysed the results the lake had drained completely, leaving only a few forlorn pools of sulphurous water.
Will looked serious as he read over the results.
“Hmmmmm. nothing is certain but it seems likely that the mountain is indeed becoming active. It would appear that the lava plug deep in the volcano’s innards has been breached and magma is seeking a way to the surface: nothing to do with our explosions by the way”
“It’s pretty likely that there will be an eruption of some kind within the next few months. However, I doubt that the scale will be very large. Chances are good that there will be very little lava actually reaching the surface, and what does escape will cool long before it reaches the base of the mountain. Gas and ash clouds may be more of a problem, but again it is likely that the eruption will take the form of a steady release of pressure, with a plume of ash-laden gas escaping from the mountain top to be blown downwind (which means to the west, across the island and out to sea). This might look alarming but should not seriously threaten even the nearest town. I’m sure the authorities will be pleased.”
“Well luckily the ship is nearly flyable anyway” said Grim. “If Taeva and I put in a late shift we should be ok by morning.”
“I’m with you” said Taeva.