Monday, July 13, 2020

Arecales Volcano

While I'm still very actively working on my maps, I don't quite have a new finished project to write about at the moment. I do have this very active stratovolcano that I mapped a while ago to share, however:



The area around the volcano has an extremely diverse array of landuses. The rough gray that covers most of the island is bare rock, essentially places where plant life has not returned since the last eruption. Upon eruption, the lahar or mudflow destroys plant life, leaving the trails of bare rock behind that I have mapped. The fact that there is so much of it signifies that the volcano is extremely active, and is perhaps in a state of perpetual activity though fumaroles along the rocky sides of the volcanoes. There are no notable examples of mudpots, and the volcano is less muddy in nature than many volcanoes in Yellowstone or the volcano by Huckleberry Springs discussed in that blog post. Since there's no limnic activity, or CO2-burdened air waves caused by trapped CO2 deposits, the entirety of the activity, and therefore the danger, is volcanic in nature.

Since there are no moraines in this environment, smoother paths carved by glacial retreat, every side of the volcano is rocky and sharp with landuses that are rough and unpredictable. Another good tag to map much of this bare rock under would be scree, the loose rock debris that often surrounds volcanoes as well as many other types of mountains. The coast is rocky, and is tagged as shingles since the rocks are not small enough to be a pebble beach and not fine enough (sand) to be a beach. Many riverbanks are also tagged as shingles. The soil is somewhat rocky, but is very well fertilized by the volcano, so plant life can easily take a hold on it. Since the map will change rather rapidly in geologic terms, think about this as a snapshot in time (though I'm not planning on updating it).

The five types of vegetation presented in this snapshot are grassland, forest, scrub, heath, and marsh. While there are high-growing grasses, they are not present on these islands, and the grassland is limited to the lowest tier of the volcano. Since trees usually don't neighbor the ocean, being susceptible to tidal variation, they are limited to 500-2000 feet away from the shore. Since the scale is so small, I avoided small bunches of forest even when it would be theoretically plausible. A thin layer of scrub is next, which consists of the smaller woody vegetation that typically seperates the forest from heath or upper grassland. The treeline is never reached on this island, as the volcano is too short even for the tropical climate, so the areas of heath and scrub represent areas where the forest was destroyed and has not yet regrown, or areas that are too steep for trees, as mentioned in the Huckleberry Springs blog. Finally, marshes are present where water collects with no outflow, often by or in places carved out by lahar or neighboring streams and lakes.

Seven streams are present on the island, occurring in valleys and all intermittent. The lack of any major rivers or notable hydrological systems can be attributed to the small scale of a volcanic island. Streams form in valleys, however, and are useful on a map for pointing out where the valleys and ridges are. Streams also facilitate grassland better than forest, so on many of them a small retreat of the forest is present. The nearest point of land is an uninhabited atoll 30 miles away, the nearest human settlement is 50 miles away, and the nearest continental point of land is over 950 miles away.















Given that the volcano is continually active, there is no permanent human settlement on the island. However, there is a small dock and a research center, with a path (no stairs, only switchbacks) up the volcano leading to a monitoring center. Other than this, the island is completely untouched.


Zooming in on the island, you can see the extreme fractalized nature of the volcano's edges, and the unpredictable ways in which the lahar spread. Disconnected areas of forest and heath represent some flatter areas where plants could grow back quicker and bands of bare rock signify places where they couldn't. You can also see cave entrances, of which there are many because of newly created lava tunnels as you approach the shore.

Thanks for reading, explore the slippy map here: https://opengeofiction.net/#map=13/9.7333/177.7619






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