24th February: ‘Southwestern Iceland was rocked by a series of earthquakes’, reported DW.com. ‘Experts say shocks from the quake, which registered 5.7 in magnitude, sparked increased volcanic activity, triggering a number of aftershocks registering over 4.0 for hours after the initial quake hit.
“It’s an intense activity zone, we are all well aware of that but I’ve never experienced or felt so many strong earthquakes in such a short period of time. It’s unusual,” as the Icelandic Meteorological Office’s (IMO) earthquake hazards coordinator Kristin Jonsdottir told Icelandic public broadcaster RUV.’
The article below appeared five days ago.
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“If an eruption occurs, it would likely mark the beginning of such a [volcanic] period – lasting a few centuries, I believe,” states Magnús Á. Sigurgeirsson, geologist at ÍSOR Iceland GeoSurvey – a consulting and research institute in the field of geothermal sciences and utilization.
“That’s at least how it has been the past three times, and even dating further back, but we don’t have as exact data available on that,” he tells Iceland Monitor.
He is referring to the uncertainty regarding whether an eruption can be expected soon on the Reykjanes peninsula, Southwest Iceland.
Magnús assembled data on the past three volcanic periods in the area. These were 3,000-3,500 years ago, 1,900-2,400 years ago, and finally between the years 800 and 1240 AD.
His information is based on geological maps of the Reykjanes peninsula and on a comprehensive book on volcanic eruptions in Iceland called Náttúruvá á Íslandi, eldgos og jarðskjálftar.
Research reveals that during the latter part of Holocene – a term used to describe a period that began about 11,700 years ago – the volcanic systems on the Reykjanes peninsula have erupted every 900 to 1100 years.
Less is known about the first part of Holocene.
Each eruption period appears to have lasted about 500 years, and during that time most of the volcanic systems appear to have been active, albeit generally not simultaneously. The volcanic activity is characterized by eruptions that each last a few decades. Lava flows from volcanic fissures that can be as long as 12 km (7.5 mi).
On the Reykjanes peninsula, there are six volcanic systems, lined up side by side, pointing from southwest to northeast. Farthest west is that of Reykjanes, then those of Svartsengi, Fagradalsfjall mountain, Krýsuvík, Brennisteinsfjöll mountains and, finally, Hengill mountain.
The last volcanic period began around the year 800 in Brennisteinsfjöll mountains and in the Krýsuvík system, creating the lava fields of Hvammahraun and Hrútafellshraun.
Full article here.
via Tallbloke’s Talkshop
March 11, 2021 at 03:48AM