Easily accessible by graded dirt road, are the Inyo
Craters. A short trail, from the parking lot, leads
up to the craters and to the lakes. The craters serve
as an example of, what was possibly, the last volcanic
activity in the area. A mild form of volcanism is indicated
here and it is thought that they were created by gases
bursting through weak spots in the earth's crust, hurling
outwards whatever was above, thus creating the two main,
funnel-shaped craters. This is thought to have occurred
relatively recently in about 1400 ad. Craters are common
in this area but the green-colored lakes in each of
these craters are very rare.
The Mono Craters are an unusual chain of obsidian domes,
approximately 2400 feet above the valley floor. They
actually approach the height of the famed volcanoes,
Stromboli and Vesuvius!
Unlike the Hawaiian lava flows, a very thick form of
lava built the Mono Craters. Some rose as gigantic columns
of obsidian, building dome-shaped mountains (the three
center domes). Others flowed over forming the domes
to the north and south. The pumice on the east side
of the craters measures 20 feet thick and stretches
east as far as the Nevada border. On the western side,
the pumice is only 5 feet thick. The craters were created
over thousands of years, mostly in recent history following
the last Ice Age (less than 10,500 years ago).
Hot springs and steam vents are still present, making
a future eruption possible. The craters can be seen
from US 395 between the northern June Lake turnoff and
Mono Lake. They may also be viewed from Hwy. 120 east.