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Abstract. Lava flows present a significant natural hazard to communities around volcanoes and are typically slow-moving (<1 to 5 cm s−1) and laminar. Recent lava flows during the 2018 eruption of Kīlauea volcano, Hawai'i, however, reached speeds as high as 11 m s−1 and were transitional to turbulent. The Kīlauea flows formed a complex network of braided channels departing from the classic rectangular channel geometry often employed by lava flow models. To investigate these extreme dynamics we develop a new lava flow model that incorporates nonlinear advection and a nonlinear expression for the fluid viscosity. The model makes use of novel discontinuous Galerkin (DG) finite-element methods and resolves complex channel geometry through the use of unstructured triangular meshes. We verify the model against an analytic test case and demonstrate convergence rates of P+1/2 for polynomials of degree 𝒫. Direct observations recorded by unoccupied aerial systems (UASs) during the Kīlauea eruption provide inlet conditions, constrain input parameters, and serve as a benchmark for model evaluation.
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Lava crickets ( Caconemobius spp.) on Hawai'i Island: first colonisers or persisters in extreme habitats?
1. Primary succession after a volcanic eruption is a major ecological process, but relatively little is known about insects that colonise barren lava before plants become established. 2. On Hawai'i Island, the endemic cricket,Caconemobius foriGurney & Rentz, 1978, is known as the first multicellular life form to colonise lava after an eruption from Kīlauea Volcano. In the Kona region, a congener,Caconemobius anahuluOtte, 1994 inhabits unvegetated lava flows from Hualālai Volcano, but little has been documented about its distribution. 3. Our aim was to characterise the presence/absence ofCaconemobiusspp.across lava flows that are largely unvegetated, but differ in age since eruption and connectivity to older flows. We used baited live traps to survey 9 month–50 year‐old Kīlauea lava flows forC. fori, and ∼220 year‐old Hualālai lava flows forC. anahulu. 4. We found no evidence thatC. forihas colonised the Kīlauea flows from the 2018 eruption. However, we did discover thatC. foriwas persistent and widespread on Kīlauea lava up to 50 years old within Hawai'i Volcanos National Park. We also capturedC. anahuluacross much of the Hualālai lava flows we surveyed in Kona. 5. We demonstrated thatC. forido not always arrive on new lava within months after an eruption, in contrast to previous reports, and that bothC. foriandC. anahulucan remain on lava longer than previously appreciated. Vegetation successional state may be more important than true age for the persistence of these endemic crickets.
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- Award ID(s):
- 1914611
- PAR ID:
- 10265618
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Ecological Entomology
- Volume:
- 46
- Issue:
- 3
- ISSN:
- 0307-6946
- Format(s):
- Medium: X Size: p. 505-513
- Size(s):
- p. 505-513
- Sponsoring Org:
- National Science Foundation
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