acquired September 3, 2013
download large image (884 KB, JPEG, 1440x960)
The Lazio region of central Italy has
many landforms of volcanic origin, including several large lakes that
mark the locations of ancient volcanoes. This photograph from an
astronaut on the International Space Station highlights two such
lakes—Lago di Vico and Lago Bracciano—located to the northwest of Rome.
Both lakes are located within calderas, large depressions that form
after violent, explosive eruptions empty a volcano’s underlying magma
chamber. Any remnants of the volcanic edifice can then collapse into the
newly-formed void, leading to the creation of large depressions. These
depressions can fill partially or completely with water, forming
permanent lakes.
Lago Bracciano (image right) is approximately 8 kilometers (5 miles)
across at its widest point, and is located 32 kilometes (20 miles)
northwest of Rome. The volcanic activity at Lago Bracciano began
approximately 600,000 years ago and continued to approximately 40,000
years ago as part of the formation of the Sabatini volcanic complex.
While part of the lake formation was due to the collapse of part of a
large magma chamber, the current caldera also was formed by movement
along numerous faults in the area—a process known as volcano-tectonic
collapse.
Located approximately 24 kilometers (15 miles) to the north-northwest
of Lago Bracciano, Lago di Vico occupies part of a caldera associated
with eruptive activity that began about 800,000 years ago and continued
until 90,000 years ago. The caldera was formed largely by the
catastrophic eruption of the Vico volcano approximately 200,000 to
150,000 years ago. The final phase of volcanic activity in the caldera
led to the formation of a small lava cone in the northeast quadrant
known as Mount Venus.
The extent of the lakes of Bracciano and Vico are readily apparent in
this image due to sunglint—light reflecting back from the water
surfaces towards the observer. This reflection gives a mirror-like
sheen to the water surfaces. Dark green forested areas associated with
parks are visible near both lakes, while light gray to white regions
indicate human settlement, such as the city of Viterbo and tilled
fields.
Astronaut photograph ISS036-E-39778
was acquired on September 3, 2013, with a Nikon D3S digital camera
using a 400 millimeter lens, and is provided by the ISS Crew Earth
Observations experiment and Image Science & Analysis Laboratory,
Johnson Space Center. The image was taken by the Expedition 36 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab
to help astronauts take pictures of Earth that will be of the greatest
value to scientists and the public, and to make those images freely
available on the Internet. Additional images taken by astronauts and
cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by William L. Stefanov, Jacobs at NASA-JSC.
- Instrument:
- ISS - Digital Camera
NASA: Italy - Lazio region - Caldera Lakes to the North of Rome - 09.21.13
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