Climate change and seismic resilience: Key considerations for Alaska’s infrastructure and built environment

Climate change is driving parallel processes such as permafrost thaw, water table fluctua- tions, and building subsidence that influence the seismic response of infrastructure systems. Alaska has experienced unprecedented levels of climatic warming, with statewide average tem- peratures increasing at a rate of about 0.4°C per decade since the 1970s, twice the global aver- age [6]. Winter temperatures have increased by an average of about 3°C since the 1950s [6]. Arctic areas are experiencing more rapid warming than the state average [7]. By 2100, Repre- sentative Concentration Pathway scenarios [8] project annual average warming of at least 4–5.5°C in the state’s northern areas and 2–3.3°C in its southern areas [7, 9]. These changes are taking place in a state with a large geographic area, spatially dispersed population (.46 inhabitants per km2), and a limited road system. Alaska is ethnically diverse, with the highest Indigenous population among US states. The state is 60% non-Hispanic white, 15% Indigenous (with 20 recognized Native languages), and 25% Asian, Black, Pacific Islander, Latino, other, or multiracial. The cultural and livelihood differences among these groups are substantial, as they are between the majority of Alaskans who live in cities, towns, and suburbs, particularly along the coast, and smaller populations in rural areas accessible only by air or water. The Alaskan economy is highly reliant on oil and gas extraction, as well as government, military, fishing, other resource extractive industries, tourism, and subsistence hunting.

The challenges of seismic activity and climate change in Alaska are intricately connected, particularly in Arctic and sub-Arctic regions. The U.S. Global Change Research Program in the Fourth National Climate Assessment notes that as the Arctic region warms due to climate change, the permafrost layer that supports infrastructure such as buildings, roads, and pipe- lines may thaw, leading to soil instability and subsidence [7]. For example, Instanes and Mjur- eke [10] used the Arctic Climate Change Impact Assessment (ACIA) climate change models to project changes in soil bearing strength for seven sites throughout Alaska. Of the seven sites considered, Bethel Alaska experienced the largest reduction in soil strength (40%) between 1999 and 2090. It should be noted that Instanes and Mjureke [10] used an identical soil profile with the same thermal properties for all of the locations; therefore, their analysis can only be used as an indication of relative climate differences between locations. Nonetheless, soil strength deterioration can increase the risk of earthquake damage in some areas. Whitehouse et al. [11] found that climate change can also influence the magnitude of glacial isostatic Fig 1. Damage caused by the 2018 Anchorage Alaska earthquake showing (a) lateral spreading along Vine Road close to Wasilla and (b) ground crack propagation along a sloping valley on the south side of Potter Creek in Anchorage. https://doi.org/10.1371/journal.pone.0292320.g001 PLOS ONE

Climate change and seismic resilience: Key considerations for Alaska’s infrastructure and built environment PLOS ONE | https://doi.org/10.1371/journal.pone.0292320 October 18, 2023 2 / 17 National Science Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.