Laacher See; also known as Lake Laach or Laach Lake, is a volcanic caldera lake with a diameter of 2 km (1.2 mi) in Rhineland-Palatinate, Germany, about 24 km (15 mi) northwest of Koblenz, 37 km (23 mi) south of Bonn, and 8 km (5.0 mi) west of Andernach. It is in the Eifel mountain range and is part of the East Eifel volcanic field within the larger Volcanic Eifel. The Eifel region located between Bonn and Trier is the most geologically active area in Germany. The German Volcanoes Route takes visitors on a tour of the top geological sites of interest to tourists in the local area across around 280 kilometers.

The Laacher See lake is the largest lake in the federal state of Rhineland-Palatinate and is a popular day trip destination. During the summer, visitors can take a cool dip in the waters, while on the eastern shore of the lake, there is something exciting waiting to be discovered. There, small bubbles rise in the water. These “mofettes” are rising carbon dioxide and reflect the volcanic history of the lake (although the lake is not a maar like the other volcanic lakes in the Eifel).
About 13,000 years ago, there were several violent eruptions of the Laacher See volcano. First, rising magma came into contact with aquiferous layers and triggered an explosion of water steam. In the following eruption phase, in a similar way to Vesuvius, several ash columns formed, the ash from which was spread widely across Europe. However, there were interruptions to this eruption. As a result, the ash columns collapsed and became hot flows of embers. The ember flows ran into the valleys towards Brohltal and Pellenz, filling them up. The cooled lava flows are called “trass”.

 Today, you can visit trass caves in the Brohltal valley, as well as an old Roman mine at Meurin, where the material was excavated.
A further eruption followed, in which basalt blocks from older lava stones surrounding the volcano were blasted outwards. These basalt blocks can be seen in the Wingertsberg volcano wall near Mendig.

The below pictures are taken by my friend Mr. Günter Ernstes, 2022

References:

1- www.eifel.info
2- https://en.wikipedia.org
3- www.sciencedaily.com