Simplified method for scenario-based risk assessment adaptation planning in the coastal zone

The development of successful coastal adaptation strategies for both the built and natural environments requires combining scenarios of climate change and socio-economic conditions, and risk assessment. Such planning needs to consider the adaptation costs and residual damages over time that may occur given a range of possible storm conditions for any given sea level rise scenario. Using the metric of the expected value of annual adaptation costs and residual damages, or another metric that can be related to the elevation of flooding, a simplified method to carry this out is presented. The approach relies upon developing damage-flooding depth probability exceedance curves for various scenarios over a given planning period and determining the areas under the curves. While the approach does have limitations, it is less complex to implement than using Monte Carlo simulation approaches and may be more intuitive to decision makers. A case study in Maine, USA is carried out to illustrate the method.     

迈向可持续发展——地质公园行动建议(英文)

From 27th to 29th, May, 2011, the participants of the 2nd International Forum on Geoparks from 5 countries gathered in Taining, Fujian Province, China. The participants discussed developing and preserving our Geoparks and Geo-heritage in sustainable ways. The forum recognized that the Geopark Program initiated by UNESCO is an efficient tool for geo-heritage protection, recreation, education and economic development. The role of capacity building in achieving sustainable development of Geoparks is significant and the potential for capacity building has not been fully realized.     

北川地区擂鼓断裂在汶川地震中的地表破裂及其意义

2008年5月12日汶川MS8.0级特大地震发生后,在北川县擂鼓地区出露了一条擂鼓同震地表破裂带,该破裂带呈近南北向展布,位于映秀－北川断裂的中北段,其北东起于擂鼓镇柳林村北部,南西止于石岩村南部,以脆性破裂为特征,分别由3条呈北北东、北西西、北北东走向的地表破裂组成,延伸长度约4～5km,并切割了多种地貌单元,其平均垂直断距为1.5m,平均水平断距为1.4m,垂直与水平断距之比为1.07∶1。通过对该地表破裂带野外测量数据、几何展布结构及其成因机制的初步分析表明： 擂鼓断裂是出露于擂鼓地区的捩断层,具有捩断层的基本特性;其主要特征包括：1)擂鼓断裂的形成是由于在汶川地震中其东西两侧逆冲块体之间的差异性运动而引起; 2)断裂呈近南北向展布,与映秀－北川主干断裂近垂直相交;3)断面倾角较陡,为高角度断面的逆断层,具有逆冲兼走滑特征。     

汶川Ms8.0地震的地表破裂过程－－以都江堰八角庙村断层擦痕剖面为例

汶川MS8.0地震在龙门山断裂带造成了严重的地表破裂,但能反映地震地表破裂过程的现象却很少,四川省都江堰市虹口乡八角庙村有一处保存基本完好的断层擦痕剖面,是惟一能反映地震地表破裂过程的露头。剖面上可见两种侧伏产状相差很大的擦痕,我们利用全站仪和GPS对擦痕进行总体和细部的测量,结果表明,一种擦痕接近垂直,侧伏角在 76°～87°之间,另一种擦痕侧伏角相对较小,介于 32°～33°之间。利用擦痕侧伏角、断层面倾角、岩石内摩擦角进行求解断层主应力方位的赤平投影,结果表明发震断层的运动方式为逆冲兼右行走滑。通过分析对比,我们认为断层面上近水平方向的擦痕切割了近垂直方向的擦痕,据此将地震的地表破裂过程分为两个阶段。阶段Ⅰ断层运动以逆冲向上为主,阶段Ⅱ以右旋走滑为主,这个结论与地震波数据反演结果是一致的。其中,阶段Ⅰ由两个子事件组成; 第一个子事件断层以接近垂直的角度逆冲向上运动,运动方向为SW85°～87°; 第二个子事件断层的运动方向发生朝向NE方向的倾斜,运动方向为SW76°～80°,表明断层运动性质为逆冲兼少量的右旋走滑。阶段Ⅱ断层的运动方向为SW32°～33°,表明这一阶段断层运动以右行走滑为主,走滑分量大于逆冲分量。     

Dynamic measurement of sediment grain compressibility at atmospheric pressure: acoustic applications

Under certain conditions, Wood's equation can be used to predict sound speed in fluid/solid-grain suspensions if the bulk moduli and densities of the grains and fluid are known. In this paper, that relationship is used to estimate grain-bulk moduli in suspensions where sound speed, fluid density, fluid bulk modulus, grain density, and particle concentrations are known or accurately measured. Measured values of grain-bulk moduli for polystyrene beads suspended in water (mean = 4.15 /spl times/ 10/sup 9/ Pa) and soda-lime glass beads suspended in a "heavy liquid" (mean = 3.8 /spl times/ 10/sup 10/ Pa) are consistent with the values of bulk moduli for polystyrene beads and soda-lime glass beads found in the literature (3.6 to 4.2 /spl times/ 10/sup 9/ Pa and 3.4 to 4.0 /spl times/ 10/sup 10/ Pa, respectively). These measurements thus provide controls, which demonstrate the validity of the suspension technique to estimate values of particle bulk modulus. The values of bulk modulus, measured using the same suspension techniques, for Ottawa sand and quartz sand grains collected from the coastal sediments of the northeast Gulf of Mexico ranged between 3.8 and 4.7 /spl times/ 10/sup 10/ Pa, with 95% confidence limits between 3.0-5.7 /spl times/ 10/sup 10/ Pa. These measured values of bulk modulus are consistent with the range of handbook values for polycrystalline quartz (3.6 to 4.0 /spl times/ 10/sup 10/ Pa). The use of the lower bulk modulus (i.e., 7.0 /spl times/ 10/sup 9/ Pa) recently suggested by Chotiros is therefore inappropriate and traditional handbook values of sediment grain-bulk moduli should be used as inputs for sediment acoustic modeling.     

Responses of estuarine phytoplankton communities to nitrogen form and mixing using microcosm bioassays

We examined the effects of different forms of nitrogen and mixed versus static conditions on the structure and function of natural Neuse River estuary phytoplankton communities incubated in 66-liter microcosms in March, May, August, and November 1999. Significant differences were found between effects of mixed versus static treatments in three of four experiments, but no differences were observed between effects of different forms of nitrogen. Mixed incubations resulted in higher contributions of diatoms to total community biomass (measured as chlorophylla) than in static tanks in May. Significantly higher rates of carbon fixation were also observed, likely due to increased suspension of diatoms in surface (illuminated) layers of the tanks. In August, we found significantly higher abundances of cyanobacteria, total community biomass, and rates of carbon fixation in static tanks than in tanks that were mixed. In November, static incubations showed significantly higher abundances of cryptophytes resulting in higher total community biomass and rates of carbon fixation in static tanks than in mixed tanks. Nitrogen additions significantly increased total community biomass relative to controls in May and August, indicating that the communities were nitrogen-limited at these times. We conclude that while nitrogen additions may result in increases in phytoplankton biomass when nitrogen is limiting, phytoplankton community structure in the Neuse River Estuary may be determined more by the hydrodynamics of the system (mixing versus stratification) than by the form of nitrogen available for growth.     

Chemical variation induced by flow differentiation in an extensive Karroo dolerite sheet,southern Namibia

Chemical relations in an extensive Karroo dolerite sheet are consistent with large-scale phenocryst redistribution during intrusion of a tholeiitic magma. Flow differentiation provides a mechanism for inward migration of early olivine, plagioclase and augite, resulting in a total phenocryst population concentrated in and roughly symmetrically distributed about the centre of the sill. The inferred early phenocryst content of the magma varies by a factor of two from 23 wt% at the margins to 50 wt% in the centre of the sill. Chilled dolerite from the sill margins is the most phenocryst-poor material and is not representative of the bulk magma. Integration over height in the sill provides the best approximation to the bulk composition. No significant lateral variation in bulk sill chemistry is detected over a distance of 20 km.     

Opening of the red sea with two poles of rotation

Previous studies have shown that the Red Sea was formed by two stages of sea-floor spreading, with a quiescent period in between. We suggest that these two phases have occurred in different directions. The shape of the central trough indicates that the present-day motion is almost E-W, whereas the total opening, deduced from the shape of the coastlines, is NE-SW. If the axial trough has opened in an E-W direction, the earlier stage of opening was in a direction which made the Dead Sea Rift fall along a small circle to the pole of early opening, and hence suggests that the Dead Sea Rift was a transform fault during this early stage. The later movement gives almost pure extension along the Dead Sea Rift, and this should be seen by normal faulting. Available first-motion studies are not precise enough to confirm or deny this hypothesis.     

How do people perceive the disclosure risk of maps? Examining the perceived disclosure risk of maps and its implications for geoprivacy protection

ABSTRACT

This research examines how people subjectively perceive the disclosure risk of a map using original data collected in an online survey with 856 participants. The results indicate that perceived disclosure risk increases as the amount of locational information displayed on a map increases. Compared to point-based maps, perceived disclosure risk is significantly lower for kernel density maps, convex hull maps, and standard deviational ellipse maps. The results also revealed that perceived disclosure risk is affected by map scale and the presence of information of other people on a map. For geomasking methods, perceived disclosure risk decreases as aggregation level increases and as relocation distance increases. However, aggregation methods (point to polygon) are more effective in preventing the re-identification of individuals when compared to relocation methods (point to point). Lastly, the perceived disclosure risk of a map that displays socially-vulnerable people is significantly higher than that of a map that displays non-vulnerable groups. Specifically, a map displaying the private locations of elementary school students has the highest perceived disclosure risk. Based on the results, a set of geoprivacy protection guidelines for mapping people’s private locations to minimize people’s perceived disclosure risk is proposed. Implications for mapping infectious diseases like the COVID-19 are also discussed.