Hekla at predawn on April 14th, 2012. (Mila webcam capture)
According to an article published today by journalist Kristján Kristjánsson on the Icelandic Internet news outlet Pressan, “Hekla is ready to erupt” and “tension is very high in the mountain”. The article, which is in Icelandic, goes on to quote (Professor) Páll Einarsson, the man who rightly won international acclaim in 2000 when he read the signs correctly and famously said that Hekla would erupt at 18:15 hours, thirty minutes before the event which duly arrived at 18:18 hours. From what the article says, it is obvious that the writer is quoting an old interview made years ago.
However, even if this article gives the impression that an eruption is imminent this is not necessarily so! First of all, neither IMO nor Almannavarnir, the organisation responsible for public safety, make any mention of noteworthy unrest at Hekla. Second, the instrumentation publicly available courtesy of the IMO show little or no signs that an eruption could be imminent even if Hekla is famous for giving little or no advance sign until less than an hour before an eruption begins.
“So what should I look for?”, you ask. Well, let me run through a few useful websites and what to look for! First of all, regularly check the IMO earthquake page for Myrdalsjökull:
IMO page for the Myrdalsjökull area June 20th, 2016. Note earthquake at Hekla, a M 1.1 at 9.6 km depth (IMO)
If the map shows earthquakes at or very close to Hekla, a look at the special page devoted to Hekla, Heklavöktun, is indicated. On this page, there are links to most instruments monitoring Hekla as well the information available from the year 2000 eruption for comparison. I have placed the relevant comments in the image captions:
Borehole strain and seismicity (IMO). Please note the scale on the strain count! This changes and is currently high but can be as low as 1/50th of the one on display. Needless to say, if the scale is set to show minor movement, these appear large without this signifying anything in particular. When it comes to earthquakes, large distant earthquakes will show up as they did during the 2014-5 Bardarbunga eruption. Make certain that an earthquake showing on this graphic is indeed at Hekla and not a distant event! At the bottom of this part of the page is a quicklink to the five strain meters.
Borehole strain at station Hekla (IMO). The strain measured varies naturally with the tides. If there is a change due to volcanic unrest, the strain will deviate sharply and unmistakably from this normal, slow undulation. Please note that the instrument is so sensitive that large earthquakes; ~M 4-5 elsewhere in Iceland and M 7 or larger worldwide, tend to show up here.
The page also has links to the three SIL-stations closest to Hekla. The image shows tremor registered at Haukadalur SIL-station during the year 2000 eruption. (IMO) Please note how very unmistakable the immediate, sharp rise is!
Finally, the page contains links to several additional webcams including the “Burfell Dalek” looking at Hekla from the North. (IMO)
There is an additional instrument monitoring Hekla available online, the Fedgar drum plot which is accessed through the IMO-supplied page “Tromlurit” or directly via the link at the bottom of the page.
Fedgar drum plot (IMO). At present, the weather is rather heavy which is the reason for the thickness of the lines. Please note that most of the earthquakes shown here are actually teleseisms from more distant quakes, something that can be confused with harmonic tremor by the untrained eye as they are very drawn-out and lack the sharp peaks of the P- and S-waves of regular tectonic earthquakes.
So, is Hekla about to erupt? To judge from what the instrumentation shows, no. The article was probably intended to attract traffic to the site rather than factual reporting. BUT! Hekla is so unpredictable and gives such scant warning that by the time I have finished writing this article and published it, Hekla could indeed be in the process of erupting!