Yellowstone Lake seems fairly dull, but appearances can be deceiving.
The bottom of Yellowstone Lake is hydrothermally active and has been shaped by huge hydrothermal explosions that could wipe us out within minutes!
Some geological features in and around Yellowstone Lake could become terrifying in a near future!
Large hydrothermal explosion craters sit in and around Yellowstone Lake. In 1962, staff at the Norris Museum witnessed “house-sized” chunks of mud being tossed above tree tops more than 1.5 miles (2.4 km) away.
Unlike volcanic explosions characterized by super-heated pyroclastic flows (hot gas, ash, rock and lava), hydrothermal explosions result from magma-heated water and steam building pressure underground.
If pressure can be released by geysers or hot springs, nothing happens. But if the pressure builds up too far, the results can range from a hearty burp to a deadly explosion of steam and shattered rock.
Explosions can result in pits or craters that range in size from a few yards to hundreds of yards, tossing debris miles away.
The last really big hydrothermal explosions were 3,000 and 14,000 years ago, based on radiocarbon dating of wood fragments found in the debris.
The largest hydrothermal explosion crater is Mary’s Bay. Since 1872, there have been 20 minor blowouts. In 1989, the Pork Chop Geyser in Norris Basin got clogged. When the pressure broke loose, rocks rained around tourists some 200 yards away.
Sites around Yellowstone Lake that were formed by hydrothermal explosions include Indian Ponds, Evil Twin over in West Thumb and Duck Lake – a crater on the edge of West Thumb Geyser Basin.
These are relatively shallow systems. In Yellowstone, there’s no evidence for a volcanic eruption triggering a hydrothermal eruption and vice versa. Heat from the magma chamber (4 to 5 miles below) is providing the energy for heating the water in the hydrothermal systems.
Big, powerful and deadly hydrothermal explosions are rare, but are more frequent than volcanic eruptions in Yellowstone.
Here a video about the the mysterious whispers heard around Yellowstone Lake. Could they be related to such explosions?
A powerful earthquake and a big landslide could displace enough water in Yellowstone Lake to uncork a hydrothermal explosion. And there are lots of landslide deposits along the shores of the lake. But it is unknown if there was just one or a series of landslides. It makes a big difference in understanding hazards associated with the lake (scientific article).