Inferred fault geometry and slip distribution of the 2010 Jiashian,Taiwan, earthquake is consistent with a thick-skinned deformation model     

Kuo-En Ching  Kaj M. Johnson  Ruey-Juin Rau  Ray Y. Chuang  Long-Chen Kuo  Pei-Ling Leu 《Earth and Planetary Science Letters》2011,301(1-2):78-86

We invert measurements of coseismic displacements from 139 continuously recorded GPS sites from the 2010, Jiashian, Taiwan earthquake to solve for fault geometry and slip distribution using an elastic uniform stress drop inversion. The earthquake occurred at a depth of ~ 23 km in an area between the Western Foothills fold-and-thrust belt and the crystalline high mountains of the Central Range, providing an opportunity to examine the deep fault structure under Taiwan. The inferred rupture plane is oblique to the prominent orientation of thrust faults and parallel to several previously recognized NW-striking transfer zones that appear to connect stepping thrusts. We find that a fault striking 318°–344° with dip of 26°–41° fits the observations well with oblique reverse-sinistral slip under a low stress drop of about 0.5 MPa. The derived geodetic moment of 2.92 × 10¹⁸ N-m is equivalent to a M_w = 6.24 earthquake. Coseismic slip is largely concentrated within a circular patch with a 10-km radius at the depth between 10 and 24 km and maximum slip of 190 mm. We suggest this earthquake ruptured the NW-striking Chishan transfer fault zone, which we interpret as a listric NE-dipping lateral ramp with oblique slip connecting stepping thrust faults (ramps). The inferred slip on the lateral ramp is considerably deeper than the 7–15 km deep detachment identified in previous studies of western Taiwan. We infer an active basal detachment under western Taiwan at a depth of at least ~ 20–23 km based on these inversion results. The earthquake may have nucleated at the base of the lateral ramp near the intersection with the basal detachment. Coulomb stress change calculations suggest that this earthquake moved several NE-striking active thrust faults in western Taiwan nearer to failure.  相似文献   

Volatile (sulphur and chlorine), major,and trace element geochemistry of mafic to intermediate tephras from the Chilean Southern Volcanic Zone (33–43°S)     

Heidi Wehrmann  Kaj Hoernle  Guillaume Jacques  Dieter Garbe-Schönberg  Kai Schumann  Julia Mahlke  Luis E. Lara 《International Journal of Earth Sciences》2014,103(7):1945-1962

Here we present the first systematic investigation of volatile geochemistry along the Southern Volcanic Zone (SVZ) of Chile. Holocene olivine-hosted melt inclusions in the most mafic tephras sampled from 16 volcanoes along the volcanic front of the SVZ between 33°S and 43°S were analysed for pre-eruptive sulphur, chlorine, and major element contents. These results are combined with trace element compositions of the host whole rocks. The highest fractionation-corrected gas contents occur in the least-degassed melt inclusions from small monogenetic cones of Los Hornitos, Cabeza de Vaca, and Apagado from both the transitional and the southern-central SVZ, reaching ~3,000 μg/g S and 1,400 μg/g Cl, while the lowest abundances of ~1,100 μg/g S and ~600 μg/g Cl were found in the central SVZ at Volcán Lonquimay, Volcán Llaima, and Volcán Villarrica. Chlorine co-varies with trace element indicators for the degree of melting and/or source enrichment, such that the lowest Cl contents are found in high-degree melts from the most depleted mantle sources. The size of the volcanic edifices correlates inversely with Cl abundances in the melt. This could reflect more extensive degassing during ascent through the complex magma plumbing systems beneath the stratovolcanoes or greater dilution during larger degrees of melting of more depleted sources, or a combination of these factors. Compared to other subduction zones, the SVZ melt inclusions exhibit Cl and S abundances in the same range as most of those from the Central American and those from the Marianas arcs.  相似文献   

Temperature in lowland Danish streams: contemporary patterns,empirical models and future scenarios     

Niels Lagergaard Pedersen  Kaj Sand‐Jensen 《水文研究》2007,21(3):348-358

Continuous temperature measurements at 11 stream sites in small lowland streams of North Zealand, Denmark over a year showed much higher summer temperatures and lower winter temperatures along the course of the stream with artificial lakes than in the stream without lakes. The influence of lakes was even more prominent in the comparisons of colder lake inlets and warmer outlets and led to the decline of cold‐water and oxygen‐demanding brown trout. Seasonal and daily temperature variations were, as anticipated, dampened by forest cover, groundwater input, input from sewage plants and high downstream discharges. Seasonal variations in daily water temperature could be predicted with high accuracy at all sites by a linear air‐water regression model (r²: 0·903–0·947). The predictions improved in all instances (r²: 0·927–0·964) by a non‐linear logistic regression according to which water temperatures do not fall below freezing and they increase less steeply than air temperatures at high temperatures because of enhanced heat loss from the stream by evaporation and back radiation. The predictions improved slightly (r²: 0·933–0·969) by a multiple regression model which, in addition to air temperature as the main predictor, included solar radiation at un‐shaded sites, relative humidity, precipitation and discharge. Application of the non‐linear logistic model for a warming scenario of 4–5 °C higher air temperatures in Denmark in 2070‐2100 yielded predictions of temperatures rising 1·6–3·0 °C during winter and summer and 4·4–6·0 °C during spring in un‐shaded streams with low groundwater input. Groundwater‐fed springs are expected to follow the increase of mean air temperatures for the region. Great caution should be exercised in these temperature projections because global and regional climate scenarios remain open to discussion. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

The surface energy balance at the Huygens landing site and the moist surface conditions on Titan     

Kaj E. Williams  Christopher P. McKay  Fredrik Persson 《Planetary and Space Science》2012,60(1):376-385

The Huygens Probe provided a wealth of data concerning the atmosphere of Titan. It also provided tantalizing evidence of a small amount of surface liquid. We have developed a detailed surface energy balance for the Probe landing site. We find that the daily averaged non-radiative fluxes at the surface are 0.7 W m^?2, much larger than the global average value predicted by McKay et al. (1991) of 0.037 W m^?2. Considering the moist surface, the methane and ethane detected by the Probe from the surface is consistent with a ternary liquid of ethane, methane, and nitrogen present on the surface with mole fractions of methane, ethane, and nitrogen of 0.44, 0.34, and 0.22, respectively, and a total mass load of ～0.05 kg m^?2. If this liquid is included in the surface energy balance, only a small fraction of the non-radiative energy is due to latent heat release (～10^?3 W m^?2). If the amount of atmospheric ethane is less than 0.6×10^?5, the surface liquid is most likely evaporating over timescales of 5 Titan days, and the moist surface is probably a remnant of a recent precipitation event. If the surface liquid mass loading is increased to 0.5 kg m^?2, then the liquid lifetime increases to ～56 Titan days. Our modeling results indicate a dew cycle is unlikely, given that even when the diurnal variation of liquid is in equilibrium, the diurnal mass variation is only 3% of the total liquid. If we assume a high atmospheric mixing ratio of ethane (>0.6×10^?5), the precipitation of liquid is large (38 cm/Titan year for an ethane mixing ratio of 2×10^?5). Such a flux is many orders of magnitude in excess of the photochemical production rate of ethane.  相似文献   

Bioaccumulation of 14C-PCB 101 and 14C-PBDE 99 in the marine planktonic copepod Calanus finmarchicus under different food regimes     

Magnusson K  Magnusson M  Ostberg P  Granberg M  Tiselius P 《Marine environmental research》2007,63(1):67-81

Bioaccumulation factors (BAFs) were determined for (14)C-PCB 101 and (14)C-PBDE 99 in the pelagic copepod Calanus finmarchicus after exposure to either contaminated water or after being fed contaminated phytoplankton (the dinoflagellate Prorocentrum minimum or the diatom Thalassiosira weissflogii). BAFs in algae range from 7.6 to 8.0 for PCB 101 and from 8.5 to 8.6 for PBDE 99. BAFs in copepods were significantly lower, 6.3-6.8 for PCB 101 and 7.6 for PBDE 99. For each compound, the BAFs in copepods were independent of what algal species they had consumed, even though the bioaccumulation of both compounds were higher in P. minimum than in T. weissflogii. The ratios between BAF and the K(ow) for PCB 101 and PBDE 99 were similar within each of the three species, but varied between species. For copepods the ratios were 2-4, for T. weissfloggii 15-22 and for P. minimum 32-40. The data strongly suggest that the two compounds bioaccumulate in a similar manner and that there is no biomagnification in the transfer between phytoplankton and herbivorous copepods.  相似文献   

Geochemical variations in the Cocos Plate subducting beneath Central America: implications for the composition of arc volcanism and the extent of the Galápagos Hotspot influence on the Cocos oceanic crust     

Seth Sadofsky  Kaj Hoernle  Svend Duggen  Folkmar Hauff  Reinhard Werner  Dieter Garbe-Schönberg 《International Journal of Earth Sciences》2009,98(4):901-913

New geochemical data from the Cocos Plate constrain the composition of the input into the Central American subduction zone and demonstrate the extent of influence of the Galápagos Hotspot on the Cocos Plate. Samples include sediments and basalts from Ocean Drilling Program (ODP) Site 1256 outboard of Nicaragua, gabbroic sills from ODP Sites 1039 and 1040, tholeiitic glasses from the Fisher Ridge off northwest Costa Rica, and basalts from the Galápagos Hotspot Track outboard of Central Costa Rica. Site 1256 basalts range from normal to enriched MORB in incompatible elements and have Pb and Nd isotopic compositions within the East Pacific Rise MORB field. The sediments have similar ²⁰⁶Pb/²⁰⁴Pb and only slightly more radiogenic ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb isotope ratios than the basalts. Altered samples from the subducting Galápagos Hotspot Track have similar Nd and Pb isotopic compositions to fresh Galápagos samples but have significantly higher Sr isotopic composition, indicating that the subduction input will have a distinct geochemical signature from Galápagos-type mantle material that may be present in the wedge beneath Costa Rica. Gabbroic sills from Sites 1039 and 1040 in East Pacific Rise (EPR) crust show evidence for influence of the Galápagos Hotspot ∼100 km beyond the morphological hotspot track.  相似文献   

Pulp and paper mill pollution and subsequent ecosystem recovery of a large boreal lake in Finland: a paleolimnological analysis     

Jarmo J. Meriläinen  Juhani Hynynen  Arja Palomäki  Heikki Veijola  Allan Witick  Kaijo Mäntykoski  Kaj Granberg  Kari Lehtinen 《Journal of Paleolimnology》2001,26(1):11-35

Sedimentary diatom frustules and chironomid remains, in addition to the chemical stratigraphy of 32 elements and resin acids, were studied from short-core samples taken from two basins and a sheltered bay of Lake Päijänne in southern Finland (about 61 °10–62 °15 N, 25 °30 E). The lake was formerly oligotrophic but has been subject to effluent loading from pulp and paper mills during the past century since the opening of the first pulp mill in the 1880s. Four developmental phases were distinguished and named mainly according to the effects found in the basin close to the pollution source: (1) the pre-industrial phase (from the 1800s to ca. 1920), including the early years of industrialization, with low impacts; (2) the phase of increasing pollution (ca. 1920–1969); (3) the phase of severe pollution (1970–1981); and (4) the water protection phase (1982 onwards).Distinct differences were observed between pelagic (diatoms) and benthic (chironomid) ecosystems in their response to pollution. Effluent loading from the pulp and paper mills had a pronounced impact on chironomid assemblages, but only a slight influence on diatoms in the basin close to the pollution source. In the southern basin, approximately 60 km downstream, an increase in acidophilous species was observed in the diatom assemblages during the early years of pollution, but changes in chironomids in this basin were negligible. The water protection work of the past 30 years, which has led to an improvement in water quality and a marked recovery of the profundal biota, has also resulted in a slight increase in primary production of the lake. The decrease in brown-coloured effluent water has led to an increase in thickness of the lake's photic productive layer, while the toxicity of the water has simultaneously diminished. Rapid changes in chironomid assemblages and sedimentation observed in the sheltered bay highlight the importance of local land-use activities as causes of environmental change in this area, and especially their effects on sedimentation and benthic life.  相似文献   

The metabolism of aquatic ecosystems: history,applications, and future challenges     

Peter?A.?StaehrEmail author  Jeremy?M.?Testa  W.?Michael?Kemp  Jon?J.?Cole  Kaj?Sand-Jensen  Stephen?V.?Smith 《Aquatic Sciences - Research Across Boundaries》2012,74(1):15-29

Measurements of the production and consumption of organic material have been a focus of aquatic science for more than 80 years. Over the last century, a variety of approaches have been developed and employed for measuring rates of gross primary production (P_g), respiration (R), and net ecosystem production (P_n = P_g − R) within aquatic ecosystems. Here, we reconsider the range of approaches and applications for ecosystem metabolism measurements, and suggest ways by which such studies can continue to contribute to aquatic ecology. This paper reviews past and contemporary studies of aquatic ecosystem-level metabolism to identify their role in understanding and managing aquatic systems. We identify four broad research objectives that have motivated ecosystem metabolism studies: (1) quantifying magnitude and variability of metabolic rates for cross-system comparison, (2) estimating organic matter transfer between adjacent systems or subsystems, (3) measuring ecosystem-scale responses to perturbation, both natural and anthropogenic, and (4) quantifying and calibrating models of biogeochemical processes and trophic networks. The magnitudes of whole-system gross primary production, respiration and net ecosystem production rates vary among aquatic environments and are partly constrained by the chosen methodology. We argue that measurements of ecosystem metabolism should be a vital component of routine monitoring at larger scales in the aquatic environment using existing flexible, precise, and durable sensor technologies. Current and future aquatic ecosystem studies will benefit from application of new methods for metabolism measurements, which facilitate integration of process measurements and calibration of models for addressing fundamental questions involving ecosystem-scale processes.  相似文献   

细粒酒精模型冰物理力学性质评价的新指标   总被引：1，自引：0，他引：1  

李志军  RiskaKaj 《海洋学报》1999,21(5):59-64

依据酒精细粒模型冰制冰过程中的物理本质和控制细粒酒精模型冰物理力学性质的物理本质,建立了一项适合于喷雾技术细粒模型冰性质评价综合指标.阐明了这一评价指标的物理意义,并给出这一指标与细粒酒精模型冰物理力学性质参数的关系.  相似文献   

Origin of isolated seamounts in the Canary Basin (East Atlantic): The role of plume material in the origin of seamounts not associated with hotspot tracks     

Xiaojun Long  Jrg Geldmacher  Kaj Hoernle  Folkmar Hauff  Jo‐Anne Wartho  C.‐Dieter Garbe‐Schnberg 《地学学报》2020,32(5):390-398

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