Abrupt climate changes and a super volcano

An extremely brief reversal of the geomagnetic field, climate variability and a super volcano
sciencecodex/41,000 years ago, a complete and rapid reversal of the geomagnetic field occured. Magnetic studies of the GFZ German Research Centre for Geosciences on sediment cores from the Black Sea show that during this period, during the last ice age, a compass at the Black Sea would have pointed to the south instead of north. Moreover, data obtained by the research team formed around GFZ researchers Dr. Norbert Nowaczyk and Prof. Helge Arz, together with additional data from other studies in the North Atlantic, the South Pacific and Hawaii, prove that this polarity reversal was a global event. Their results are published in the latest issue of the scientific journal "Earth and Planetary Science Letters".
What is remarkable is the speed of the reversal: "The field geometry of reversed polarity, with field lines pointing into the opposite direction when compared to today's configuration, lasted for only about 440 years, and it was associated with a field strength that was only one quarter of today's field," explains Norbert Nowaczyk. "The actual polarity changes lasted only 250 years. In terms of geological time scales, that is very fast." During this period, the field was even weaker, with only 5% of today's field strength. As a consequence, the Earth nearly completely lost its protection shield against hard cosmic rays, leading to a significantly increased radiation exposure.
This is documented by peaks of radioactive beryllium (10Be) in ice cores from this time, recovered from the Greenland ice sheet. 10Be as well as radioactive carbon (14C) is caused by the collision of high-energy protons from space with atoms of the atmosphere.
The Laschamp event
The polarity reversal now found with the magnetisation of Black Sea sediments has already been known for 45 years. It was first discovered after the analysis of the magnetisation of several lava flows near the village Laschamp near Clermont-Ferrand in the Massif Central, which differed significantly from today's direction of the geomagnetic field. Since then, this geomagnetic feature is known as the 'Laschamp event'. However, the data of the Massif Central represent only some point readings of the geomagnetic field during the last ice age, whereas the new data from the Black Sea give a complete image of geomagnetic field variability at a high temporal resolution.
Abrupt climate changes and a super volcano
Besides giving evidence for a geomagnetic field reversal 41,000 years ago, the geoscientists from Potsdam discovered numerous abrupt climate changes during the last ice age in the analysed cores from the Black Sea, as it was already known from the Greenland ice cores. This ultimately allowed a high precision synchronisation of the two data records from the Black Sea and Greenland. The largest volcanic eruption on the Northern hemisphere in the past 100 000 years, namely the eruption of the super volcano 39400 years ago in the area of today's Phlegraean Fields near Naples, Italy, is also documented within the studied sediments from the Black Sea. The ashes of this eruption, during which about 350 cubic kilometers of rock and lava were ejected, were distributed over the entire eastern Mediterranean and up to central Russia. These three extreme scenarios, a short and fast reversal of the Earth's magnetic field, short-term climate variability of the last ice age and the volcanic eruption in Italy, have been investigated for the first time in a single geological archive and placed in precise chronological order.

 

Volcanic Activity on the Rise

extinctionprotocol/ Klyuchevskoy volcano erupts in Kamchatka

KAMCHATKA – The Klyuchevskoy volcano, the highest active volcano in Eurasia, has started erupting in Kamchatka, in the Russian Far East. The luminescence over the volcano summit is evidence that glowing lava is flowing in the crater. The volcano may start blowing out ash any moment now. The Level of Concern Colour Code has been raised to Yellow, which is a potential danger warning for aircraft. The giant volcano last erupted from September 2009 to December 2010, and it began to again wake up in June this year. Klyuchevskoy volcano is 4,750 meters above sea. –VOR

COLOMBIA - According to the Volcanological and Seismological Observatory of Manizales, an earthquake measuring 2.6 on the Richter scale occurred yesterday at 11:54 am. The statement also notes that the incident “is associated with rock fracturing within the volcanic edifice.” The volcano-tectonic earthquake was presented to the southeast of the main dome at a depth of 12.33 miles. Although the movement was felt in the district Tapias, rural Ibagué, Eduardo Rodríguez, director of the Departmental Committee for Risk Management, confirmed that no emergencies have been reported so far. The Cerro Machin volcano alert remains yellow. There have been three earthquakes reported in the vicinity of the volcano within a week. On Sunday two movements were recorded at 9:32 and 9:35 pm with a magnitude of 4.6 and 3.9 on the Richter scale, respectively, located 12 kilometers southeast of depth to the main dome. The two municipalities where the tremors were felt are Cajamarca and Ibague. Cerro Machin last erupted 800 years ago. –Elnuevodia (translated)

El Hierro: It seems a new earthquake swarm has started at El Hierro volcano yesterday, when the number of quakes rose from an average of about 8-10 to 23 quakes per day. Today, so far there have been 14 events recorded, and their number is likely to rise further. The quakes are very small (mostly under M1, largest M2.0) and are concentrated at about 10 km depth in the western El Golfo and scattered in the SW part of the island at greater depths.

Iceland: A new earthquake swarm occurred over the weekend on the Iceland’s Reykjanes peninsula, on the volcanic rift zone about 12 km SW of Brenisteinsfjöll volcano. The largest quake was a M3.8 event at 5 km depth on Friday at 19:42 UTC.

Yellowstone: A minor seismic swarm occurred at Yellowstone, but falls into what is normal activity at a large active caldera. -Volcano Discovery