Mapping of hazard from rainfall-triggered landslides in developing countries: Examples from Honduras and Micronesia

Loss of life and property caused by landslides triggered by extreme rainfall events demonstrates the need for landslide-hazard assessment in developing countries where recovery from such events often exceeds the country's resources. Mapping landslide hazards in developing countries where the need for landslide-hazard mitigation is great but the resources are few is a challenging, but not intractable problem. The minimum requirements for constructing a physically based landslide-hazard map from a landslide-triggering storm, using the simple methods we discuss, are: (1) an accurate mapped landslide inventory, (2) a slope map derived from a digital elevation model (DEM) or topographic map, and (3) material strength properties of the slopes involved. Provided that the landslide distribution from a triggering event can be documented and mapped, it is often possible to glean enough topographic and geologic information from existing databases to produce a reliable map that depicts landslide hazards from an extreme event. Most areas of the world have enough topographic information to provide digital elevation models from which to construct slope maps. In the likely event that engineering properties of slope materials are not available, reasonable estimates can be made with detailed field examination by engineering geologists or geotechnical engineers. Resulting landslide hazard maps can be used as tools to guide relocation and redevelopment, or, more likely, temporary relocation efforts during severe storm events such as hurricanes/typhoons to minimize loss of life and property. We illustrate these methods in two case studies of lethal landslides in developing countries: Tegucigalpa, Honduras (during Hurricane Mitch in 1998) and the Chuuk Islands, Micronesia (during Typhoon Chata'an in 2002).     

Producing nature and making the state: Ordenamiento territorial in the Pacific lowlands of Colombia

In this paper, we explore how ordenamiento territorial, a territorial zoning policy in the 1991 Colombian Constitution remakes nature and helps constitute the state in the “economically backward” but “biodiversity rich” Pacific lowlands region. We draw on Gramscian insights on hegemony and the importance of conjunctures to trace how changes in the new Constitution and global biogeopolitics reconfigure nature and state power through the mandates of sustainable development, economic growth, and the conservation of biological and cultural diversity. Finally, we contribute to the literature on political ecology by showing how the political power of the state, nature, and capital are interwoven materially and symbolically in complex and contradictory ways.     

On the modeling of the state dependency of granular soils

Experimental studies have revealed that principal elements of the mechanical behavior of granular soils like the angles of internal peak friction and dilatancy are highly influenced by the combined effect of soil density and mean principal effective stress. In the literature, various empirical correlations between these elements and some parameters indicating soil state have been suggested. Herein, by using two well-known empirical expressions for state dependent peak friction and dilatancy angles, proper constitutive equations are derived and implemented in a stress ratio-based bounding surface plasticity framework. It is shown that the modified model is capable of simulating sand response in either loose or dense states using a unique set of parameters.     

Variability of the Indo-Pacific Ocean exchanges

The ECCO–GODAE global estimate of the ocean circulation 1992–2007 is analyzed in the region of the Indonesian Throughflow (ITF), including the Southern Ocean flow south of Australia. General characteristics are an intense month-to-month noise, only weak trends, and an important annual cycle (which is not the focus of attention). Apart from the details of the unresolved flows within the various passages, and right on the equator, the region and its large-scale climate effects appears to be accurately diagnosed by large-scale geostrophic balance, so that the ITF can be calculated either from the upstream or the downstream balanced flow (but no simple reference level can be defined). The INSTANT program occurs during a more or less typical three-year period. Indications of response to the large 1997–1998 El Niño are weak.     

Historical channel narrowing along the Rio Grande near Albuquerque,New Mexico in response to peak discharge reductions and engineering: magnitude and uncertainty of change from air photo measurements

Over the last century, geomorphic processes along the Middle Rio Grande have been altered by flood control and bank stabilization projects, intensified land and water use, and climate change. In response to potential risks to infrastructure and ecological integrity, recent (1985–2008) adjustment was investigated and historic (1918–1985) changes in Rio Grande channel planform through the Albuquerque, New Mexico, area were reviewed, especially in relation to changes in annual peak discharge and river engineering measures. Using a GIS, channel characteristics were digitized from georeferenced photographs and analyzed with particular attention to quantifying potential measurement error and its propagation. Error associated with average channel widths and channel area ranged between 4 and 13%. For smaller polygons, e.g. islands, error was higher (11 to 40% for width and >200% for area) because width error is large relative to polygon width. Between 1918 and 1963, average channel widths decreased 8 m/yr, from 516 ± 67 m to 176 ± 7 m, mostly due to decreasing peak flows and the implementation of flood control and other engineering measures. From 1985 to 2008, widths decreased 0·7 m/yr, from 176 ± 23 m to 146 ± 5 m, accompanied by an increase in vegetated island area which largely coincided with low flow periods. Narrowing was concentrated at tributary inputs and in the upstream part of the reach, where bedload trapping by Cochiti Dam has caused degradation. Bank protection structures and dense vegetation limit bank erosion in the reach, but erosion is significant where expanding islands, incision, and increased meandering force water against banks. Copyright © 2010 John Wiley & Sons, Ltd.     

Tectonic and climatic controls on Holocene channel migration,incision and terrace formation by the Rio Grande in the Palomas half graben,southern Rio Grande rift,USA

In order to evaluate potential effects of tectonics and climate change on the behaviour of the axial Rio Grande in the Rio Grande rift, a 16·5 km stretch of modern floodplain and Holocene terraces were mapped in the tectonically active Palomas half graben, south‐central New Mexico, USA. In addition, 51 cores and natural exposures were logged and 20 radiocarbon dates were obtained from charcoal, bulk organic matter, mollusc shells and pedogenic calcite. The Holocene alluvium comprises four terraces above the modern floodplain, each of which formed by a period of river incision followed by stability and renewed floodplain construction to a level below that of the previous terraces. Estimated times of incision between Terraces I and II, II and III, and III and IV are after 12 400, 8040 to 5310, and 760 to 550 yr bp , respectively, whereas the incision between Terrace IV and the modern floodplain occurred within the last 260 years. Although there is some evidence for tectonic control on river behaviour in the southern part of the basin, terrace formation is interpreted as being related to climate change, with periods of incision corresponding to times of increased aridity and low sediment/water discharge ratio in the Rio Grande. This process may have resulted from a reduction in intensity and magnitude of summer storms which supply sediment to the axial river, coupled with an increase in spring discharge peak caused by snowmelt in upstream mountain catchments.     

惯性测量中计算重力元素的新方法

本文首先介绍了用惯性技术测定重力元素的基本原理,并分析了惯性测量系统目前采用的重力元素计算方法的优缺点;并在此基础上提出了一个计算重力元素的新方法。理论分析及防真结果均表明:相对于目前所用方法而言,本文给出的方法不仅计算工作量少、内存量小,而且求得的结果精度高。     

Suitability mapping for rice cultivation in Benue State,Nigeria using satellite data

ABSTRACT

With rising population, decline in soil productivity and land-based conflicts, the per-capita land availability for cultivation is rapidly decreasing within Benue State, a largely agrarian and small-holder setting. This study attempts a local-level support for the actualisation of Sustainable Development Goal Number 2 (“end hunger, achieve food security and improved nutrition, and promote sustainable agriculture”) by 2030. Using Multi-Criteria Decision Making (MCDM) method, remote sensing data from Climate Research Unit (CRU) and in-situ data from Nigeria Meteorological Agency (NIMET) were analyzed by GIS techniques to map the suitability of rice cultivation in the study area, with the integration of Normalized Difference Vegetation Index (NDVI), land cover, slope, temperature, precipitation and soil parameters (cation exchange capacity, pH, bulk density, organic carbon). We apply the various statistical parameters that include mean spatial NDVI; correlation coefficient, standard deviation and Root Mean Square (RMS) between CRU and NIMET data. Spatial regression trend analysis is conducted between CRU precipitation and NDVI and between CRU temperature and NDVI from 1985 to 2015. The results reveal that NDVI in highly suitable rice planting regions is higher than marginally suitable regions except in the months of October and November, which shows that the highly suitable regions will yield better than the marginally suitable regions during the dry season. Additionally, NDVI is seasonally bimodal in response to precipitation, meaning that vegetation vigor is more dependent on precipitation than temperature. Finally, the correlation coefficient, standard deviation and RMS between CRU and NIMET precipitation data shows 0.42, 108, and 110, respectively, while these three factors between CRU and NIMET temperature data shows 0.88, 1.60, and 0.86, respectively. In conclusion, the MCDM approach reveals that upland is more suitable for rice cultivation in Benue State when comparing with the area provided by the Global Land Cover and National Mappings Organization (GLCNMO) data.     

A microscopic equation of state for protoneutron stars

We study the structure of protoneutron stars within the finite-temperature Brueckner–Bethe–Goldstone many-body theory. If nucleons, hyperons, and leptons are present in the stellar core, we find that neutrino trapping stiffens considerably the equation of state, because hyperon onsets are shifted to larger baryon density. However, the value of the critical mass turns out to be smaller than the “canonical” value 1.44M _⊙. We find that the inclusion of a hadron-quark phase transition increases the critical mass and stabilizes it at about 1.5–1.6M _⊙.      

Invertebrate traces in pseudo–coprolites from the upper Cretaceous Marília Formation (Bauru Group), Minas Gerais State,Brazil

Pseudo–coprolites are inorganic structures often confused with fossil faeces. The absence of some diagnostic features, such as inclusions, coprofabrics, grain adhesion, and defined shape, suffices to disregard these structures as coprolites. Herein we revise the so–called “coprolites” from the Serra da Galga Member of the Marília Formation (Maastrichtian of Bauru Group, Paraná Basin), at “Ponto 1 do Price” locality near the town of Peirópolis (Uberaba municipality, Minas Gerais State, Brazil) and conclude that they are, in fact, pseudo–coprolites related to calcretes. These data also agree with the geological setting of “Ponto 1 do Price”, composed mainly of coarse sandstones and conglomerates, in which these pseudo–coprolites were found. In addition, some of these specimens exhibit superficial traces, here described as a new boring ichnospecies, Asthenopodichnium fallax isp. nov., produced by invertebrates in Late Cretaceous fresh–water settings of Brazil.