Geology topics

Christoper Hamilton

Publications and source records attributed to Christoper Hamilton.

3 recordsLinked to original sources

USGS2025

Growth of a passive lava lake during the 2020–2021 eruption of Kīlauea volcano, Hawaii

We investigate the growth of a passive lava lake in Halemaʻumaʻu crater during the December 2020 to May 2021 eruption of Kīlauea volcano, Hawaii. Fed by vents above their surfaces, the formation of passive lava lakes in topographic lows is an important process in the growth of basaltic volcanoes. We captured visible and thermal images during 17 helicopter overflights and applied structure-from-motion photogrammetry to create digital elevation models and orthomosaics of Halemaʻumaʻu. These data products allowed us to track eruptive activity and processes. The bulk time-averaged discharge rate (TADR) in December 2020 initially exceeded 100 m 3 s –1 but decreased to < 10 m 3 s –1 within seven days. By February 2021, TADR was < 2 m 3 s –1 and continued to decrease until the eruption ended in May 2021. A total volume of 40.6 ± 0.5 × 10 6 m 3 of lava filled Halemaʻumaʻu to a depth of 225 m. As TADR decreased, the lake progressively developed an immobile, solidified crust, beginning with surfaces farthest from the vent. This immobile surface rose endogenously, whereas exogenous surface rise occurred near the vent. Eruptive activity at a vent ended when the level of the lake surface exceeded that of the vent, which we attribute to the effects of lava sitting above the vent on ascending magma. Regular helicopter overflights, combined with field observations and the extensive monitoring network at Kīlauea, generated an unprecedented density of observations that provide insights into the emplacement of passive lava lakes and how these eruptions wane and end.

Hawaii↗

USGS2021

Bridging the research-implementation gap in avian conservation with translational ecology

The recognized gap between research and implementation in avian conservation can be overcome with translational ecology, an intentional approach in which science producers and users from multiple disciplines work collaboratively to co-develop and deliver ecological research that addresses management and conservation issues. Avian conservation naturally lends itself to translational ecology because birds are well studied, typically widespread, often exhibit migratory behaviors transcending geopolitical boundaries, and necessitate coordinated conservation efforts to accommodate resource and habitat needs across the full annual cycle. In this perspective, we highlight several case studies from bird conservation practitioners and the ornithological and conservation social sciences exemplifying the 6 core translational ecology principles introduced in previous studies: collaboration, engagement, commitment, communication, process, and decision-framing. We demonstrate that following translational approaches can lead to improved conservation decision-making and delivery of outcomes via co-development of research and products that are accessible to broader audiences and applicable to specific management decisions (e.g., policy briefs and decision-support tools). We also identify key challenges faced during scientific producer–user engagement, potential tactics for overcoming these challenges, and lessons learned for overcoming the research-implementation gap. Finally, we recommend strategies for building a stronger translational ecology culture to further improve the integration of these principles into avian conservation decisions. By embracing translational ecology, avian conservationists and ornithologists can be well positioned to ensure that future management decisions are scientifically informed and that scientific research is sufficiently relevant to managers. Ultimately, such teamwork can help close the research-implementation gap in the conservation sciences during a time when environmental issues are threatening avian communities and their habitats at exceptional rates and at broadening spatial scales worldwide.

Ornithological Applications↗

USGS2017

The vanishing cryovolcanoes of Ceres

Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic domes viscously relax, precluding ancient domes from recognition. We use numerical models to predict flow velocities of Ahuna Mons to be 10–500 m/Myr, depending upon assumptions about ice content, rheology, grain size, and thermal parameters. Slower flow rates in this range are sufficiently fast to induce extensive relaxation of cryovolcanic structures over 10 8 –10 9 years, but gradual enough for Ahuna Mons to remain identifiable today. Positive topographic features, including a tholus underlying Ahuna Mons, may represent relaxed cryovolcanic structures. A composition for Ahuna Mons of >40% ice explains the observed distribution of cryovolcanic structures because viscous relaxation renders old cryovolcanoes unrecognizable.

Geophysical Research Letters↗