Please send me the answers to the following activities:
Activity 1: Observe the gently sloping terrain at this location. How do you think it would it compare to the appearance of a shield volcano on Mars?
Activity 2: Imagine the volcanic activity that may have occurred here at Mauna Kea in the past. How do you think it compares to the volcanic history of Mars' shield volcanoes like Olympus Mons?
Activity 3: Standing at the earthcache coordinates on a typical clear day you can see the summits of five shield volcanoes. Kohala to the Northeast. Mauna Kea to the southeast. Mauna Loa to the south. Hualalai to the southwest. Haleakala to the north. On an extremely clear day you can see West Maui Mountain and Kaho’olawe to the west of Haleakala. How many could you see on your visit?
Activity 4: Observe the lava rocks around you. There are two main types of lava flows in Hawaii. "Ropey" and smooth pahoehoe lava and a’a lava that does not flow as far, is sharp, and form clinkers when flowing. Which of the two types is present at the Earthcache coordinates?
Activity 5: Post a picture showing the viewing conditions on the day you visited the Earthcache.
Mahalo!
Welcome to the "Planetary Geology on Earth: Shield Volcanoes" Earthcache! If you're standing at the earthcache coordinates, you're currently on the slopes of Mauna Kea, a classic example of a shield volcano. This geological adventure will take you on a journey to explore the fascinating similarities and differences between shield volcanoes here on Earth, particularly in Hawaii, and those on Mars. Together, we’ll uncover how these volcanic features connect two worlds while highlighting what makes them unique.
Similarities:
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Basaltic Composition: Shield volcanoes on both Mars and Hawaii are primarily composed of basaltic lava, which is relatively low in viscosity. This property allows the lava to flow easily, forming the broad, gently sloping shape typical of shield volcanoes.
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Eruption Style: Non-explosive eruptions characterize shield volcanoes on both planets. Lava flows steadily from fissures or vents, creating expansive lava fields rather than violent explosions.
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Gentle Slopes: The slopes of shield volcanoes on Mars and in Hawaii are relatively shallow due to the fluid nature of the basaltic lava. As the lava spreads out horizontally, it builds the characteristic wide and gently sloped volcanic profile.
Differences:
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Size: Mars is home to the largest shield volcanoes in the solar system. Olympus Mons, the largest volcano on Mars (and the tallest mountain in the solar system), rises approximately 72,000 feet and spans a diameter of about 370 miles. In comparison, Mauna Kea, although the tallest mountain on Earth from its base to summit (32,696 feet from the ocean floor), is much smaller.
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Atmosphere: Mars has a very thin atmosphere composed primarily of carbon dioxide, which influences volcanic activity. With little atmospheric pressure, lava flows more easily, potentially creating longer flows than on Earth. Hawaii's shield volcanoes erupt in a denser atmosphere, which affects the behavior of volcanic gases and lava flows in ways that aren’t observed on Mars.
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Tectonic Setting: Hawaiian shield volcanoes form as the Pacific Plate moves over a hotspot, where molten material from the mantle rises to the surface. Over time, as the plate moves, the volcano is carried away from the hotspot and becomes extinct. On Mars, shield volcanoes like Olympus Mons form over stationary hotspots without the influence of tectonic plate movement, allowing them to grow much larger without being shifted away from the magma source.
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Age and Activity: Hawaiian shield volcanoes are still active today, with periodic eruptions shaping the islands. Martian shield volcanoes, by contrast, are extinct, with their last eruptions occurring millions of years ago. This difference in activity reflects the unique geological histories of Earth and Mars.