STUDY OF THE LAVA FLOW HAZARD ZONING BASED ON THE KINEMATIC THERMO-RHEOLOGICAL MODEL:EXAMPLE STUDY FOR THE ASHIKULE VOLCANO,XINJIANG          下载免费PDF全文

PAN Bo  CHENG Tao  WAN Yuan  YU Hong-mei  XU Jian-dong 《地震地质》2017,39(4):721-734

The lava flow hazard is an important and frequent disaster for residents in the volcanic area. In this paper, we focus on the lava flow inundation hazard zoning based on the example case of the Ashikule volcano in Xinjiang, China. Firstly, the parameters of magma such as density, viscosity and temperature are calculated by the empirical formula of magma utilizing results of previous field geological survey and petrology analysis. Then, using the kinematic thermo-rheological model, we simulated the inundation area of lava flow from Ashi volcano at the effusion rates of 200m³/s and 500m³/s. The simulation results of Ashi volcano well coincide to the geological map and verify that the method and parameters are valid. Then the applied simulations were carried out to calculate the lava flow inundation area in future eruption at Ashi, Wuluke and Daheishan crater with different effusion rates. At last, according to the analysis of the applied simulation results and drawing lessons from the foreign disaster zoning method, the four-level hazard zoning was built and set with different colors. The first level with red color is the extra-dangerous zone that is always inundated in any eruption but only distributes near the lava spillway of the crater. The second level with orange color is the dangerous zone that is inundated in the medium scale eruption. The third level with yellow color is the sub-dangerous zone that is corresponding to the large eruption. The fourth level with blue color is the potential dangerous zone that is only inundated in the extra-large eruption. In addition, we put forward the suggestion to respond to and avoid the disaster in future. Although China has not been affected by the lava flow for nearly three hundred years, the prospective study in this paper will lay the foundation for the study of related disasters, and provide the reference for the major construction projects in the volcanic area.  相似文献   

Sidewall erosion: Insights from in situ-produced 10Be concentrations measured on supraglacial clasts (Mont Blanc massif,France)     

A.-C. Sarr  J.-L. Mugnier  R. Abrahami  J. Carcaillet  L. Ravanel 《地球表面变化过程与地形》2019,44(10):1930-1944

Sidewall erosion because of rockfalls is one of the most efficient erosional processes in the highest parts of mountain ranges; it is therefore important to quantify sidewall erosion to understand the long-term evolution of mountainous topography. In this study, we analyse how the ¹⁰Be concentration of supraglacial debris can be used to quantify sidewall erosion in a glaciated catchment. We first analyse, in a glaciated catchment, the cascade of processes that move a rock from a rockwall to a supraglacial location and propose a quantitative estimate of the number of rockfalls statistically mixed in a supraglacial sand sample. This model incorporates the size of the rockwall, a power law distribution of the size of the rockfalls and the mean glacial transport velocity. In the case of the Bossons glacier catchment (Mont Blanc massif), the ¹⁰Be concentrations obtained for supraglacial samples vary from 1.97 ± 0.24 to 23.82 ± 1.68 × 10⁴ atoms g⁻¹. Our analysis suggests that part of the ¹⁰Be concentration dispersion is related to an insufficient number of amalgamated rockfalls that does not erase the stochastic nature of the sidewall erosion. In the latter case, the concentration of several collected samples is averaged to increase the number of statistically amalgamated rockfalls. Variable and robust ¹⁰Be-derived rockwall retreat rates are obtained for three distinct rockfall zones in the Bossons catchment and are 0.19 ± 0.08 mm year⁻¹, 0.54 ± 0.1 mm year⁻¹ and 1.08 ± 0.17 mm year⁻¹. The mean ¹⁰Be retreat rate for the whole catchment (ca. 0.65 mm year⁻¹) is close to the present-day erosion rate derived from other methods. © 2019 John Wiley & Sons, Ltd.  相似文献   

The Relation of Standard Metabolic Rate to Water Temperature and Body Weight of Schlegels Black Rockfish （ Sebastodes Fuscescens）     

马志敏  孙耀  张波  唐启升 《海洋通报(英文版)》2004,6(1):80-87

Standard metabolic rates of Schlegels black rockfish with different body weights are determined in laboratory by using the flow-through respirometer at 11.2℃, 14.7℃, 18.0℃ and 23.6℃. The results indicate that the standard metabolic rates increase with the increase of body weight at different temperatures. Relationship between them could be described as Rs=α lnW^b. The mean of standard metabolic rate is significantly different among groups, but the b values are not. The standard metabolic rates of amended standard body weights decrease with the increase of temperature, and the mean of standard metabolic rate is also significantly different among groups when the standard body weights are 48.6g, 147.9g, and 243.1g.Relationship between them could be described as Rsw = m e^-hT. The relations of standard metabolic rate (Rs) or relative metabolic rate (Rs) to body weight and temperature yield the following equations:Rs=1.160W^0.752-e^-9.494/7 and Rs‘=1.160W^0.254 e^-9.494/7.  相似文献   

Evolution of Modern Yellow River Delta Coast     

尹延鸿  周永青  丁东 《海洋通报(英文版)》2004,6(2):34-44

This paper deals with the development and evolution of modem Yellow River delta and the erosion or deposition rates of its different sections. In June, 1996.Yellow Rivers terminal course was artificially turned eastwards to empty into the sea and then the 1 lth lobe of the modem Yellow River delta began to form. This course change may mark the beginning of the 3rd subdelta formation. As a result of that. the Yellow River delta advances towards east by north with the 1st, 2nd and 3rd subdeltas arranged in succession. Coast zone in the deltaic area is divided into 7 different sections according to their different erosion or deposition rates: the relatively stable section from Dakou River to Shunjiang Stream, the weakly retreating section from Shunjiang Stream to the Tiaohe River mouth, the strongly retreating section from the Tiaohe River mouth to the station 106. the artificially stable section due to stone dam protection from the station 106 to Gudong Oilfield, the strong deposition section from Gudong Oilfield to Dawenliu Haipu, the weakly deposition section from Dawenliu Haipu to the Zimai Stream mouth, and the stable section from the Zimai Stream mouth to the Jiaolai River mouth. It is predicted that the erosion and deposition situations of the sections will nearly remain the same in 10 years, but the retreating and silting-up rates will tend to become slower gradually. Human activities have an evident influence on the changes of the coastline.  相似文献   

Vertical accretion rates in fluvial systems: ­a comparison of volumetric and depth‐based estimates     

Barbara Rumsby 《地球表面变化过程与地形》2000,25(6):617-631

A wide range of approaches has been adopted for collecting and reporting vertical accretion rates, hence evaluation of results from different catchments, or even from different reaches within the same basin, is difficult as they may not be directly comparable. The present study compares depth‐ and volume‐based estimates of sediment accumulation for well‐dated vertical accretion sequences at Broomhaugh Island in the Tyne basin, northern England. High resolution dating control (based on heavy metal stratigraphy and cartography) coupled with detailed reconstruction of channel geometry allows accumulation rates to be calculated for the last 300–400 years. The results show a marked disparity in the magnitude and pattern of vertical accretion rates between the two approaches. The average annual thickness of sediment increases progressively, with a six‐fold difference between the seventeenth and twentieth centuries. The volume figures are more consistent, with a two‐fold difference between the highest and lowest rates, both of which occurred in the twentieth century. A major control on vertical accretion is found to be changing channel shape and capacity. Enlargement of the channel by 76 per cent since the seventeenth century, associated with channel bed incision, has resulted in fewer overbank flows. Hence floods, with their associated suspended sediment loads, which once inundated the floodplain are now confined within the channel. The reduced areal extent of surfaces available for deposition has resulted in greater annual thickness of sediment accumulated, despite an overall reduction in volume. This study emphasizes that caution is needed when attempting to identify causal linkages between changes in sedimentation rates and catchment land use and/or climatic factors and the geomorphological setting of the site must be taken into account. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Influence of ground motion intensity on the effectiveness of tuned mass dampers     

Ricardo Soto-Brito  Sonia E. Ruiz 《地震工程与结构动力学》1999,28(11):1255-1271

The effectiveness of Tuned Mass Dampers (TMD) on buildings subjected to moderate and high-intensity motions is analysed. First, the response of a 22-storey four-bay reinforced concrete non-linear frame with a TMD is studied for motions with different intensities. Several values of the relevant parameters are assumed in the analyses. Then, equivalent single-degree-of-freedom systems with TMDs and without them are defined and analysed under the action of ground motions with intensities associated with different return intervals at the site where the structures are located. Vulnerability curves for the systems are obtained based on the probabilities of reaching two different performance limit states. The expected annual rate of exceedance of each limit state is calculated. The results show that the effectiveness of TMDs is higher for systems with small non-linearity produced by small and moderate earthquakes, than for systems with high non-linear behaviour, generally associated with high-intensity motions. Some recommendations about the applicability of TMD are given. Copyright © 1999 John Wiley & Sons Ltd.  相似文献   

Energy rates due to Fe isotopes during presupernova evolution of massive stars     

《New Astronomy》2024

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中国对虾(Fenneropenaeus Chinensis)自然感染与人工感染WSSV抗病力的比较          下载免费PDF全文

张天时  李素红  孔杰  王清印  孟宪红  罗坤 《海洋与湖沼》2010,41(5):763-768

取30个通过人工授精和自然交尾建立的中国对虾家系,分别进行人工感染和自然感染实验。实验过程中,两实验组样本总体存活率在35%左右时统计各家系的存活率,以分析其抗白斑综合征病毒情况。用四格表的卡方检验分析中国对虾各家系存活率,结果发现23个家系的存活率在两种感染方式实验间差异不显著(P0.05),两种感染方式实验间家系存活率一致性为77%。用独立样本T检验对两种感染方式实验中4个杂交组合的存活率进行比较,结果发现4个杂交组合的存活率在两种感染方式实验间差异不显著(P0.05),说明人工感染和自然感染实验对中国对虾抗病力的反映情况基本是一致的。另外,对两个实验中各家系的抗病力进行分析,综合结果表明有5个家系对WSSV可能有较强的抗病力。  相似文献   

Glacial activity and paraglacial landsliding in the Devensian Lateglacial: evidence from Craig Cerrig-gleisiad and Fan Dringarth,Fforest Fawr (Brecon Beacons), South Wales     

Richard A. Shakesby  John A. Matthews 《Geological Journal》1996,31(2):143-157

The tongue-shaped mass of debris and associated ridges on the cirque floor below Craig Cerrig-gleisiad, Brecon Beacons National Park is important and controversial because it has been attributed to more than one glacier advance during the Late Devensian. A new origin is proposed involving landslide development from the collapse of part of the western headwall followed by a single phase of glacier development in the Loch Lomond Stadial (Younger Dryas), which reworked the landslide sediments. Evidence for this landslide, which provides useful criteria for differentiating moraines formed by small glaciers from landslides, lies in tension cracks, backward-tilted blocks and bedrock joints dipping out of the western headwall, together with lateral levées, upstanding termini and angular clasts with only occasional, indistinct striae on the tongue-shaped mass, which is interpreted as a flowslide. Glacier reworking of debris in the upper part of the Cwm Cerrig-gleisiad landslide is indicated by subparallel ridges rising to 20 m above the cirque floor containing abraded clasts (16-32% striated). This interpretation is supported by a comparison with the morphological and sedimentary characteristics of a neighbouring landslide at Fan Dringarth, where no glacier developed in the Loch Lomond Stadial. The existence of paraglacial landsliding has significant palaeoenvironmental implications leading to: (1) erroneously large estimates of equilibrium line depression ($Δ$ELA) in the Loch Lomond Stadial; (2) consequent underestimates of summer palaeotemperatures and/or overestimates of the contribution of wind-drifted snow to glacier accumulation; and (3) larger moraines than usual and overestimation of the efficacy of glacial erosion because of antecedent processes.  相似文献   

The SPICE project: Calibrated cosmogenic 26Al production rates and cross-calibrated 26Al /10Be, 26Al/14C,and 26Al/21Ne ratios in quartz from the SP basalt flow,AZ, USA     

《Quaternary Geochronology》2022

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