Present-day stress orientations and tectonic provinces of the NW Borneo collisional margin

Extent: 15p.Borehole failure observed on image and dipmeter logs from 55 petroleum wells across the NW Borneo collisional margin were used to determine maximum horizontal stress (σH) orientations; combined with seismic and outcrop data, they define seven tectonic provinces. The Baram Delta–Deepwater Fold-Thrust Belt exhibits three tectonic provinces: its inner shelf inverted province (σH is NW-SE, margin-normal), its outer shelf extension province (σH is NE-SW, margin-parallel), and its slope to basin floor compression province (σH is NW-SE, margin-normal). In the inverted province, σH reflects inversion of deltaic normal faults. The σH orientations in the extension and compression provinces reflect deltaic gravitational tectonics. The shale and minibasin provinces have been recognized in offshore Sabah. In the shale province, σH is N010°E, which aligns around the boundary of a massif of mobile shale. Currently, no data are available to determine σH in the minibasin province. In the Balingian province, σH is ESE-WNW, reflecting ESE absolute Sunda plate motions due to the absence of a thick detachment seen elsewhere in NW Borneo. The Central Luconia province demonstrates poorly constrained and variable σH orientations. These seven provinces result from the heterogeneous structural and stratigraphic development of the NW Borneo margin and formed due to complex collisional tectonics and the varied distribution and thicknesses of stratigraphic packages.Rosalind C. King, Mark R. P. Tingay, Richard R. Hillis, Christopher K. Morley, and James Clar

A method of determining where to target surveillance efforts in heterogeneous epidemiological systems

The spread of pathogens into new environments poses a considerable threat to human, animal, and plant health, and by extension, human and animal wellbeing, ecosystem function, and agricultural productivity, worldwide. Early detection through effective surveillance is a key strategy to reduce the risk of their establishment. Whilst it is well established that statistical and economic considerations are of vital importance when planning surveillance efforts, it is also important to consider epidemiological characteristics of the pathogen in question—including heterogeneities within the epidemiological system itself. One of the most pronounced realisations of this heterogeneity is seen in the case of vector-borne pathogens, which spread between ‘hosts’ and ‘vectors’—with each group possessing distinct epidemiological characteristics. As a result, an important question when planning surveillance for emerging vector-borne pathogens is where to place sampling resources in order to detect the pathogen as early as possible. We answer this question by developing a statistical function which describes the probability distributions of the prevalences of infection at first detection in both hosts and vectors. We also show how this method can be adapted in order to maximise the probability of early detection of an emerging pathogen within imposed sample size and/or cost constraints, and demonstrate its application using two simple models of vector-borne citrus pathogens. Under the assumption of a linear cost function, we find that sampling costs are generally minimised when either hosts or vectors, but not both, are sampled

Flood potential of South Prairie Creek, Pierce County, Washington /

"Prepared in cooperation with Pierce County Department of Public Works."Includes bibliographical references (p. 73-75).Mode of access: Internet

Flood-hazard mapping in Honduras in response to Hurricane Mitch /

Includes bibliographical references (p. 38-39).Mode of access: Internet

Surface-water hydrology and runoff simulations for three basins in Pierce County, Washington /

Shippling list no.: 96-0345-P.Includes bibliographical references (p. 101-102).Mode of access: Internet

Channel-planform evolution in four rivers of Olympic National Park, Washington, USA: the roles of physical drivers and trophic cascades

Identifying the relative contributions of physical and ecological processes to channel evolution remains a substantial challenge in fluvial geomorphology. We use a 74-year aerial photographic record of the Hoh, Queets, Quinault, and Elwha Rivers, Olympic National Park, Washington, USA, to investigate whether physical or trophic-cascade-driven ecological factors – excessive elk impacts after wolves were extirpated a century ago – are the dominant drivers of channel planform in these gravel-bed rivers.We find that channel width and braiding show strong relationships with recent flood history. All four rivers widened significantly after having been relatively narrow in the 1970s, consistent with increased flood activity since then. Channel planform also reflects sediment-supply changes, evident from landslide response on the Elwha River. We surmise that the Hoh River, which shows a multi-decadal trend toward greater braiding, is adjusting to increased sediment supply associated with rapid glacial retreat. These rivers demonstrate transmission of climatic signals through relatively short sediment-routing systems that lack substantial buffering by sediment storage. Legacy effects of anthropogenic modification likely also affect the Quinault River planform. We infer no correspondence between channel evolution and elk abundance, suggesting that trophic-cascade effects in this setting are subsidiary to physical controls on channel morphology. Our findings differ from previous interpretations of Olympic National Park fluvial dynamics and contrast with the classic example of Yellowstone National Park, where legacy effects of elk overuse are apparent in channel morphology; we attribute these differences to hydrologic regime and large-wood availability

Recharge from precipitation in three small glacial-till-mantled catchments in the Puget Sound Lowland, Washington /

Shipping list no.: 97-0240-P.Includes bibliographical references (p. 69-72).Mode of access: Internet

Results of the eruptive column model inter-comparison study

To improve our understanding of the physics of volcanic plumes and their interaction with the atmosphere, increasingly sophisticated numerical models of eruptive columns have been developed by a growing number of research groups. These models are different in their design and scope, but all have the fundamental goal of characterizing the dynamics of volcanic plume formation and ultimately providing estimates of source conditions. Descriptions of volcanic columns (or plumes, we use the terms interchangeably in this paper) are important for hazard mitigation because they can be used in models that forecast the dispersion of ash and hazardous gases in the atmosphere. The accuracy of tephra dispersal forecasts is strongly dependent on the source term, which describes both the mass eruption rate of volcanic emissions and their initial vertical distribution in the atmosphere. However, until now there has not been a systematic effort to compare how these source terms are derived. For this study, we have brought together 13 different models to perform a set of simulations using the same input parameters, so that results can be meaningfully compared and evaluated. The motivation is twofold: (1) to provide a conceptual overview of what the various models can accomplish, and (2) to target specific areas for further exploration by the research community as a whole.AC was partially supported by a grant of the International Research Promotion Office Earthquake Research Institute, the University of Tokyo. AC, GM, AN, MdMV, TEO and MC were partially supported by the EU-funded project MEDiterranean SUpersite Volcanoes (MEDSUV) (grant n. 308665). AVE acknowledges NSF Postdoctoral Fellowship EAR1250029 and a USGS Mendenhall Fellowship. MIB was supported partially by NSF-IDR and AFOSR. AJH, MJW, and JCP were partially supported bythe NERC-funded projectVanaheim (grantno. NE/I01554X/1) and the EU-funded project FutureVolc (grant no. 308377). FG, GC, ST, and EK were partially supported by INSU, CNRS. We wish to thank T. Koyaguchi, S. Solovitz, and an anonymous reviewer for constructive suggestions that improved the quality of the manuscript.Peer ReviewedPostprint (author's final draft