It is quiet in Iceland at the moment. There are so few earthquakes in fact that yesterday (or two days ago) no earthquake was recorded in Icelandic Meteorological Office SIL system for good 10 hours (or something like it) according to geologist that I spoke with yesterday. I am not sure why this happens in Iceland, but it does and not just Iceland. This type of quiet period happens all over the Atlantic rift zone. The weather in Iceland has also not been good, a lot of storms this year and that has been dropping chances of proper detection of earthquakes. This mostly applies to small earthquakes. I don’t know for how long this quiet period is going to last. As for the year 2013, it is one of the most quiet years that I can remember. I have been watching activity in Iceland for since the year 1994, or when I was 14 years old.
Thanks to donations I was able to buy backup power for Böðvarshólar geophone station (website here). This backup power is not meant to keep the station alive for hours, but just for 8 to 10 minutes if the power goes out. It is also meant to keep the electricity the station gets stable and without any problems. Electricity problems can and often do shorten the hardware lifespan, this is I hope going to prevent such issues and problems.
Blog post updated at 19:50 UTC.
Hi Jon,
Why is then that we see in several of the SILS around Katla, Torfajokull and Vatnajokull, several individual spikes, in the tremor graphs? Are those not earthquakes that are not being listed by the IMO? Some days ago, this was observed in Katla and Oraefajokull and those quakes were not listed. After many hours, the quakes finally appeared. It appears it has not been an automatic detection for the last few days. Notice the possible earthquakes around the Torfajokull region, north of Katla, east of Hekla, and west of Hamarinn.
http://hraun.vedur.is/ja/oroi/index.html
It has been extremely cold in Iceland for the past two days, with frost doing down to -25C in some places. This means there is a lot of frost quake activity going on.
Frost quake happens when water breaks rock as it freezes. They do register on SIL stations, but as earthquakes they have low quality and are almost never located manually or automatic. Most of the activity for past few days is this frost quake activity. I expect it to stop as it is going to get warmer in next few days in Iceland.
IMHO, many of the webicorder data indicates long-period vibration is/was occurring, with a pronounced “Ramp up” and “Ramp down” period over most of the day on 12/06.
Ice-quakes I would think would be best seen as short period “spikes”?
Unless really bad weather is present, I’d suggest there was tremor present, and not a bunch of “snap, crackle and pop” type of activity.