On February 6th of 2023, two major earthquakes which were both in the magnitude 7 range struck
separate major fault lines in south central Turkey. Thereafter, the respective faults
which they occurred on lit up like a christmas tree, allowing people to easily see the fault
lines due to the distributions of aftershocks. However, due to stress release, some aftershocks
occurred outside of these faults at more distant locations. Two of these quakes were of small
magnitude, registering in the magnitude 3 range, but interestingly occurred adjacent to the active
volcano known as Mount Erciyes. Mount Erciyes is considered to be active as it has erupted during
the Holocene period, producing 4 distinct lava domes and one maar explosion crater. While this
might sound concerning when taken out of context, these two earthquakes are not a cause for concern,
as they appear to be isolated events related to small regional faults which were not directly
underneath the volcano. And even if they were determined to be volcanic in origin,
it would not be unexpected. Minor earthquake swarms often occur at nearby volcanoes after
a large magnitude earthquake, such as when a magnitude 7.3 earthquake in California during
1992 triggered minor quake swarms at the volcanoes known as Clear Lake, the Long Valley Caldera,
Lassen Peak, and Mount Shasta. None of these volcanoes erupted due to this sequence and the
same is most likely true with the large quakes that occurred on February 6th of 2023 in Turkey.
With this being said, why does the eastern three fifths of Turkey have volcanoes in the
first place, as the plate boundaries are not causing any subduction there
and no mantle hotspots underly the country? The answer is for the same reason there in
occasional volcanism on the edges of the Colorado Plateau, a process known as lithospheric drip.
Although what causes this process to begin is unclear, sometimes a piece of lithosphere may
start to sink lower into the mantle. This occurs in a process similar to sap dripping from a tree.
It forms a distinct drop over time, which then breaks off, while also creating empty space.
Material from the lower mantle then rushes upwards to fill the empty space, creating a large amount
of uplift which in this case resulted in the Antolian Plateau via repeated occurrences of this
process. This also on occasion sends molten rock into the crust via intrusions which occasionally
reach the surface and erupt, producing a chain of volcanoes. However, due to the nature of the crust
this often results in highly viscous lavas and explosive eruptions involving andesite,
dacite, or rhyolite, although it can also involve less viscous lavas as shown by the existence of
the Mount Tendurek shield volcano just south of a more viscous composition stratovolcano,
Mount Ararat. Strangely, in this type of fairly unique geologic setting, volcanoes do occasionally
follow a pattern where closely spaced volcanoes erupt together in a brief geologic timespan. For
example, it was unusual that Mount Ararat produced a highly explosive eruption in 1840 only to be
followed by an eruption of Mount Tendurek 15 years later. Both volcanoes have not erupted since. Or,
in 7500 BCE and 6900 BCE both the Mount Hasan and Mount Erciyes volcanoes erupted about the
same time. In the Colorado Plateau which also has lithospheric drip, 3 volcanoes erupted at
about the same time approximately 900 years ago and all have not erupted since. However, just
because one volcano erupts in a lithospheric drip geologic setting does not automatically indicate
that another separate volcano which is nearby will also erupt, as plenty of isolated single
eruptions not paired with other nearby volcanoes erupting have occurred in such a setting.
However, in Turkey unlike in the Colorado Plateau, volcanism is dominantly explosive rather than
dominantly effusive. Although small explosive eruptions are far more common, this has allowed
for rare large caldera forming eruptions to occur such as a VEI 7 explosive eruption which produced
a dense rock equivalent of 40 cubic kilometers of volcanic rock at Mount Erciyes 2.52 million years
ago. Ash and pyroclastic flow deposits produced by this and other large eruptions during the last 10
million years ended up constructing a series of ash pillars at a site 50 kilometers to the west.
Because of this unique geologic setting and the lack of magmatic quakes caused by aftershocks in
recent days, as only tectonic ones occurred, the February 6th magnitude 7 earthquakes and
its aftershocks are highly unlikely to cause a volcanic eruption in Turkey at the present.
Thanks for watching! If you would like to request a specific topic, please leave a comment below.
Additionally, I would like to thank this channel's patrons on Patreon and channel members on YouTube!