Laacher See
Encyclopedia
(ˈlaːxɐ ˈzeː) or Laach Lake (in English) is a caldera lake
and a potentially active volcano, in Rhineland-Palatinate
, Germany
, situated close to the cities of Koblenz
(24 km), and Bonn
(37 km), and closest to the towns Andernach
(8 km), and Mayen
(11 km). The caldera lake lies just 8 km from the river Rhine at Andernach. Just like the nearby 'Wehrer Kessel' volcano and Rieden volcano, the Laacher See volcano forms a volcanic caldera
in the Eifel
mountain range. It is part of the area called "East Eifel volcanic field
".
The great Eifel lake takes its name from the Old High German
word "lacha" which in turn is derived from Latin
"lacus" as English "lake". Thus the name literally means "Lake of the Lake" similar to the "Loch Lochy
" in the Scottish Highlands
with the same meaning.
The lake lies 259 m above sea level, is 8 km in circumference, and surrounded by a ring of high hills. The water is blue, very cold and bitter to the taste. The lake has no natural outlet and so the water level changes considerably due to evaporation and rainfall conditions. On the western side lies the Benedictine monastery of Maria Laach Abbey
(), founded in 1093 by Henry II of Laach of the House of Luxembourg
, first count palatine of the Rhine who has had his castle opposite to the monastery above the eastern lakeside.
The caldera was formed after the colossal Laacher See eruption dated to 12,900 years ago. The remaining crust collapsed into the empty magma chamber below, probably two or three days after the eruption. An estimated 6 km³ of magma was erupted, producing around 16 km³ of tephra. This massive eruption thus had a Volcanic Explosivity Index
(VEI) of 6, and was larger than the colossal 1991 eruption of Mount Pinatubo
(Philippines) which also had a VEI of 6 (10 km³ of tephra erupted).
Tephra deposits from the eruption dammed the Rhine, creating a 140 sqkm lake. When the dam broke, an outburst flood swept downstream, leaving deposits as far away as Bonn.
The Laacher eruption coincides with the onset of the abrupt Younger Dryas
re-glaciation, which brought renewed very cold conditions to the northern hemisphere from 12.9 to 11.6 ka. However, any relationship between this climate change and the eruption is speculative; eruptions of the size of the Laacher See eruption usually cause only short-term global cooling.
Remains of this eruption can be found all over Europe and the tephra
is often used for dating of sediments. A number of unique mineral
s can be found in the region, and quarries
mine the stone as a building material
.
The Laacher See is a potentially active volcano, proven by seismic activities and heavy thermal anomalies under the lake. Carbon dioxide
gas from magma still bubbles up at the southeastern shore, and scientists believe that a new eruption could happen at any time, which today, even with a much smaller Volcanic Explosivity Index, would result in a major disaster, especially considering that Germany is a heavily populated country and this caldera lies just 8 km from the Rhine at Andernach.
Crater lake
A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...
and a potentially active volcano, in Rhineland-Palatinate
Rhineland-Palatinate
Rhineland-Palatinate is one of the 16 states of the Federal Republic of Germany. It has an area of and about four million inhabitants. The capital is Mainz. English speakers also commonly refer to the state by its German name, Rheinland-Pfalz ....
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, situated close to the cities of Koblenz
Koblenz
Koblenz is a German city situated on both banks of the Rhine at its confluence with the Moselle, where the Deutsches Eck and its monument are situated.As Koblenz was one of the military posts established by Drusus about 8 BC, the...
(24 km), and Bonn
Bonn
Bonn is the 19th largest city in Germany. Located in the Cologne/Bonn Region, about 25 kilometres south of Cologne on the river Rhine in the State of North Rhine-Westphalia, it was the capital of West Germany from 1949 to 1990 and the official seat of government of united Germany from 1990 to 1999....
(37 km), and closest to the towns Andernach
Andernach
Andernach is a town in the district of Mayen-Koblenz, in Rhineland-Palatinate, Germany, of currently about 30,000 inhabitants. It is situated towards the end of the Neuwied basin on the left bank of the Rhine between the former tiny fishing village of Fornich in the north and the mouth of the...
(8 km), and Mayen
Mayen
Mayen is a town in the Mayen-Koblenz District of the Rhineland-Palatinate Federal State of Germany, in the eastern part of the Volcanic Eifel Region. As well as the main town, there are five further settlements which are part of Mayen, they are: Alzheim, Kürrenberg, Hausen-Betzing, Hausen and Nitztal...
(11 km). The caldera lake lies just 8 km from the river Rhine at Andernach. Just like the nearby 'Wehrer Kessel' volcano and Rieden volcano, the Laacher See volcano forms a volcanic caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
in the Eifel
Eifel
The Eifel is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the south of the German-speaking Community of Belgium....
mountain range. It is part of the area called "East Eifel volcanic field
Volcanic field
A volcanic field is an area of the Earth's crust that is prone to localized volcanic activity. They usually contain 10 to 100 volcanoes, such as cinder cones and are usually in clusters. Lava flows may also occur...
".
The great Eifel lake takes its name from the Old High German
Old High German
The term Old High German refers to the earliest stage of the German language and it conventionally covers the period from around 500 to 1050. Coherent written texts do not appear until the second half of the 8th century, and some treat the period before 750 as 'prehistoric' and date the start of...
word "lacha" which in turn is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
"lacus" as English "lake". Thus the name literally means "Lake of the Lake" similar to the "Loch Lochy
Loch Lochy
Loch Lochy is a large freshwater loch in Lochaber, Highland, Scotland. With a mean depth of , it is the third deepest loch of Scotland.-Geography:...
" in the Scottish Highlands
Scottish Highlands
The Highlands is an historic region of Scotland. The area is sometimes referred to as the "Scottish Highlands". It was culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands...
with the same meaning.
The lake lies 259 m above sea level, is 8 km in circumference, and surrounded by a ring of high hills. The water is blue, very cold and bitter to the taste. The lake has no natural outlet and so the water level changes considerably due to evaporation and rainfall conditions. On the western side lies the Benedictine monastery of Maria Laach Abbey
Maria Laach Abbey
Maria Laach Abbey is a Benedictine abbey situated on the southwestern shore of the Laacher See , near Andernach, in the Eifel region of the Rhineland-Palatinate in Germany. It is a member of the Beuronese Congregation within the Benedictine Confederation...
(), founded in 1093 by Henry II of Laach of the House of Luxembourg
House of Luxembourg
The House of Luxembourg was a late medieval German dynasty, which between 1308 and 1437 ruled the Holy Roman Empire, twice interrupted by the rivaling House of Wittelsbach.-History:...
, first count palatine of the Rhine who has had his castle opposite to the monastery above the eastern lakeside.
The caldera was formed after the colossal Laacher See eruption dated to 12,900 years ago. The remaining crust collapsed into the empty magma chamber below, probably two or three days after the eruption. An estimated 6 km³ of magma was erupted, producing around 16 km³ of tephra. This massive eruption thus had a Volcanic Explosivity Index
Volcanic Explosivity Index
The Volcanic Explosivity Index was devised by Chris Newhall of the U.S. Geological Survey and Stephen Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions....
(VEI) of 6, and was larger than the colossal 1991 eruption of Mount Pinatubo
Mount Pinatubo
Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Tri-Cabusilan Mountain range separating the west coast of Luzon from the central plains, and is west of the dormant and...
(Philippines) which also had a VEI of 6 (10 km³ of tephra erupted).
Tephra deposits from the eruption dammed the Rhine, creating a 140 sqkm lake. When the dam broke, an outburst flood swept downstream, leaving deposits as far away as Bonn.
The Laacher eruption coincides with the onset of the abrupt Younger Dryas
Younger Dryas
The Younger Dryas stadial, also referred to as the Big Freeze, was a geologically brief period of cold climatic conditions and drought between approximately 12.8 and 11.5 ka BP, or 12,800 and 11,500 years before present...
re-glaciation, which brought renewed very cold conditions to the northern hemisphere from 12.9 to 11.6 ka. However, any relationship between this climate change and the eruption is speculative; eruptions of the size of the Laacher See eruption usually cause only short-term global cooling.
Remains of this eruption can be found all over Europe and the tephra
Tephra
200px|thumb|right|Tephra horizons in south-central [[Iceland]]. The thick and light coloured layer at center of the photo is [[rhyolitic]] tephra from [[Hekla]]....
is often used for dating of sediments. A number of unique mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s can be found in the region, and quarries
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...
mine the stone as a building material
Building material
Building material is any material which is used for a construction purpose. Many naturally occurring substances, such as clay, sand, wood and rocks, even twigs and leaves have been used to construct buildings. Apart from naturally occurring materials, many man-made products are in use, some more...
.
The Laacher See is a potentially active volcano, proven by seismic activities and heavy thermal anomalies under the lake. Carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
gas from magma still bubbles up at the southeastern shore, and scientists believe that a new eruption could happen at any time, which today, even with a much smaller Volcanic Explosivity Index, would result in a major disaster, especially considering that Germany is a heavily populated country and this caldera lies just 8 km from the Rhine at Andernach.