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Hazard assessment of remote volcanic islands provides many challenges compared to other volcanoes and volcanic fields. Here we present the first systematic volcanic hazard assessment of Jan Mayen Island, a remote island located in the North-Atlantic Ocean and home to the northernmost active subaerial volcano in the world (Beerenberg Volcano), and we discuss some of the challenges and characteristics of performing a volcanic hazard assessment of a remote volcanic island. Jan Mayen has had at least five eruptions since its discovery at the start of the 17th century. Its Holocene volcanism is mainly characterized by eruptions with styles ranging from Hawaiian to Strombolian, but also by lava domes and Surtseyan eruptions. Based on field data, remote images, topographic data, past data, and computer simulations, our study evaluates the spatial probability of new vents opening, estimates eruption recurrence rates, simulates various eruption scenarios, and produces hazard maps for the different scenarios. This work shows where the hazards of ash fall, and lava flows are more likely to affect the built infrastructure on Jan Mayen Island. This hazard assessment will assist emergency planning and the determination of future land use on the island.

The objectives of R/V Neil Armstrong cruise AR35-04 (Fig. 1) were to survey the flanks of the Reykjanes Ridge and determine the timing, geometry and associated geophysical characteristics of the large-scale tectonic reorganizations that occurred there in the Paleogene and continue to the present (Fig. 2). The North Atlantic plate boundary between what is today the Bight Fracture Zone and Iceland, a distance of nearly 1000 km, was originally a linear orthogonally-spreading ridge that became abruptly fragmented in a stair-step fashion following a change in plate motion [Smallwood and White, 2002]. Its subsequent evolution involved the systematic and progressive removal of offsets from north to south to re-establish its original linear configuration [Hey et al., 2016; Martinez and Hey, 2017], even though this required the ridge to then spread obliquely, since the new spreading direction remained stable. These tectonic reorganizations took place within the region of influence of the Iceland “hotspot” which creates a strong gradient in mantle melting along the ridge, increasing crustal thicknesses by ~3-4 km and decreasing ridge axis depths by ~ 3000 m between the Bight Fracture Zone and Iceland [Louden et al., 2004]. A mantle gradient in melting properties (compositional and/or thermal) is presumably what results in the regional residual basement depth anomaly that extends throughout this region of the North Atlantic from the Greenland-Iceland-Faroe Ridge to south of the Bight Fracture Zone. This gradient in mantle properties with distance from the Iceland hotspot apparently had strong modulating effects on the tectonic reorganizations: the initial segment lengths and offsets appear in regional magnetic anomaly and satellite-derived gravity maps to be smaller toward Iceland and the segments evolved to re-establish the linear ridge configuration more quickly to the north [Hey et al., 2016]. As both kinematic and “hotspot” effects influence their development, the Reykjane, This work was funded by NSF grant OCE-1756760. The Marine Advanced Technology and Education program supported the participation of the MATE interns. An InterRidge Cruise Bursary supported the participation of Dr. Dominik Palgan.

We provide the first documentation of tectonic deformation resulting from a volcanic eruption on the island of Jan Mayen. Vertical displacement of about 14 m southwest of the stratovolcano Beerenberg is associated with an eruption in ad 1732 on its southeastern flank. The age of the uplift event is bracketed by radiocarbon-dated driftwood buried by material deposited due to uplift, and by tephra from this eruption. Constraints, inferred from radiocarbon ages alone, allow for the possibility that uplift was completed prior to the ad 1732 eruption. However, the occurrence of tephra in the sediment column indicates that some displacement was ongoing during the eruption but ceased before the eruption terminated. We attribute the tectonic deformation to intrusion of shallow magma associated with the volcanic eruption. Our results complement previous studies of volcanic activity on Jan Mayan by providing precise age constraints for past volcanic activity. Also, it raises new hypotheses regarding the nature, timing and prevalence of precursor tectonic events to Jan Mayan eruptions. The uplift caused the complete isolation of a coastal lake by closing its outlet to the sea, thus landlocking the facultative migratory fish species Arctic charr (Salvelinus alpinus).