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- #541
Grindavik's opening started off quietly enough, with just a few more people coming in per news reports yesterday -- the number is expected to increase over time.
It's not the nation's #1 port in terms of annual fish haul, as far as I can tell, but Grindavik does make a significant yearly contribution to the total (aaand I can't find the link with numbers -- sorry!).
Also, Iceland has few such harbors on its southern coast, so they really do need this opening for business.
But it makes the job of public safety authorities difficult -- the local police chief expressed his concerns in an interview yesterday -- and it has the volcanologists apparently working extra hard to get people to understand the uncertainty in all this.
At least that's the impression I got while reading today's IMO update. Via GT:
A real forecasting nightmare.
It's not the nation's #1 port in terms of annual fish haul, as far as I can tell, but Grindavik does make a significant yearly contribution to the total (aaand I can't find the link with numbers -- sorry!).
Also, Iceland has few such harbors on its southern coast, so they really do need this opening for business.
But it makes the job of public safety authorities difficult -- the local police chief expressed his concerns in an interview yesterday -- and it has the volcanologists apparently working extra hard to get people to understand the uncertainty in all this.
At least that's the impression I got while reading today's IMO update. Via GT:
Landris and magma accumulation under Svartsengi continues
Model calculations show that the volume of magma is now about 2/3 of what was accumulated before the last eruption, on August 22
22.10.2024
Updated October 22 at 15:20
- GPS measurements and model calculations in the Svartsengis area show that landrising and magma accumulation continue
- Based on continued magma inflow at a similar rate, the lower uncertainty limit on magma volume can be expected to be reached at the beginning of November
- The risk assessment is valid until October 29, all things being equal
Landris and magma accumulation under Svartsengi continues at a similar pace to the last few weeks. Earthquake activity has increased slightly in the last few days, although not much, about five earthquakes per day in the magma corridor. The largest measured M1.5 in size.
Lessons learned from previous magma flows and eruptions are useful in estimating how much magma must be added beneath Svartsengi to trigger the next event. The period in which magma flows and even volcanic eruptions are considered to be more likely is marked by lower and upper uncertainty limits
Model calculations based on GPS data show that the volume of magma is now approximately 2/3 of what it accumulated before it erupted last August 22. Based on continued magma inflow at a similar rate, it can be expected that the lower uncertainty limit on the volume of magma will be reached at the beginning of November.
If a significant increase in seismic activity is measured at a similar time, it can be assumed that the probability of a new magma flow and a possible volcanic eruption has begun to increase. The probability of that will gradually increase as more magma is added and seismic activity increases.
A graph showing the development of magma accumulation and the estimated total amount of magma in the magma chamber under Svartsengi from October 25. The total volume of magma under Svartsengi is now approximately 2/3 of what accumulated before it erupted last August 22.'
Volume estimated by model calculations
The volume of the magma that has accumulated under Svartsengi since the end of the last eruption is estimated according to model calculations at 14 million cubic meters. It is estimated that about 24 million cubic meters of magma was released from the magma chamber in the last eruption, which began on August 22nd last, and was the largest eruption in this sequence of events. In these model calculations, the uncertainty is +/- 5 million cubic meters. The volume of magma under Svartsengi will therefore be brought to a position similar to that before the last eruption when it reaches the interval delimited by the "lower uncertainty limit" (19 million cubic meters) and the "upper uncertainty limit" (29 million cubic meters).
The models, which are based on GPS data and are updated daily, indicate how much volume has accumulated since the last magma flow and can be used to estimate when the uncertainty limit is reached. The models are based on an estimated magma inflow at any given time, and small changes in that flow can affect the final estimate. It is difficult to estimate how far beyond the previous limit on the volume of magma can increase before eruption begins. The trend has been that the time between eruptions is getting longer, as the amount of magma needed to trigger the next magma flow or eruption seems to increase with time. It may be necessary to assume that the risk of an eruption is considered high for several weeks before the magma flow and possible eruption begins.
A real forecasting nightmare.