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[1] Anomalous volcanism and tectonics between near-ridge mantle plumes and mid-ocean ridges provide important insights into the mechanics of plume-lithosphere interaction. We present new observations and analysis of multibeam, side scan sonar, sub-bottom chirp, and total magnetic field data collected during the R/V Melville FLAMINGO cruise (MV1007; May-June, 2010) to the Northern Galápagos Volcanic Province (NGVP), the region between the Galápagos Archipelago and the Galápagos Spreading Center (GSC) on the Nazca Plate, and to the region east of the Galápagos Transform Fault (GTF) on the Cocos Plate. The NGVP exhibits pervasive off-axis volcanism related to the nearby Galápagos hot spot, which has dominated the tectonic evolution of the region. Observations indicate that $94% of the excess volcanism in our Copyright 2012 by the American Geophysical Union 1 of 31 survey area occurs on the Nazca Plate in three volcanic lineaments. Identified faults in the NGVP are consistent with normal ridge spreading except for those within a $60 km wide swath of transform-oblique faults centered on the GTF. These transform-oblique faults are sub-parallel to the elongation direction of larger lineament volcanoes, suggesting that lineament formation is influenced by the lithospheric stress field.We evaluate current models for lineament formation using existing and new observations as well as numerical models of mantle upwelling and melting. The data support a model where the lithospheric stress field controls the location of volcanism along the lineaments while several processes likely supply melt to these eruptions. Synthetic magnetic models and an inversion for crustal magnetization are used to determine the tectonic history of the study area. Results are consistent with creation of the GTF by two southward ridge jumps, part of a series of jumps that have maintained a plume-ridge separation distance of 145 km to 215 km since $5 Ma.

The locations of a large number of earthquakes recorded at Rabaul caldera in Papua New Guinea from late 1983 to mid-1985 have produced a picture of this active caldera's structural boundary. The earthquake epicenters form an elliptical annulus about 10 kilometers long by 4 kilometers wide, centered in the southern part of the Rabaul volcanic complex. A set of events with well-constrained depth determinations shows a ring-fault structure that extends from the surface to a depth of about 4 kilometers and slopes steeply outward from the center of the caldera. This is the first geophysical data set that clearly outlines the orientation of an active caldera's bounding faults. This orientation, however, conflicts with the configuration of many other calderas and is not in keeping with currently preferred models of caldera formation.

The geological and archaeological signatures al the site of Kupona na Dari on the Willaumez Peninsula, West New Britain provide important new data about human colonisation of the Bismarck Archipelago. Analyses of the stratigraphy and weathering of paleosols and manuporls. when combined with fission track. radiocarbon, and luminescence dating, indicate that the site was first occupied at about 35-45.000 years ago. During the whole peri(Kl of occupation, people were exposed to a series of volcanic events which varied in terms of tbeir potential impacts on the local environment. A PIXE-PIGME characterisation study of the obsidian artefacts at tbe site demonstrates that from the earliest period stone resources were acquired from outcrops located across a relatively large region. When compared with Early-Middle Holocene assemblages from nearby localities, the Pleistocene stone tool technology differs in only a few minor respects. From this analysis we infer tbat groups were mobile in both periods, but slightly different strategies for tbe procurement and maintenance of tbe stone tools were required for tbe more extensive ranges exploited during the Pleistocene. The inter-disciplinary study of Kupona na Dari concludes that colonisation comprised a long term process of settling into this volcanically active environment. Due to variability in the environments tbat people encountered, the pattern of colonisation may not have been similar across the entire Bismarck Archipelago, RT: Anthropology. Tbe Australian Museum,

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