The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
K Nagarajoo - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the Earth Movement over the Equatorial Region by using the Ionosonde Observation Data
International Journal of Integrated Engineering, 2009Co-Authors: K NagarajooAbstract:This paper focuses on the ionospheric variability observed in the F2 layer during a seismic event at equatorial region. The analysis using critical frequency, fc, shows that there is relationship between the ionospheric variations and the occurrence of Earthquake. The fc of the F2 layer (fcF2) and the minimum virtual height (h’F2) data were measured using ground-based ionosonde that has been stationed in Wireless and Radio Science Centre (WARAS), UTHM (1.860 N, 103.080 E). Two statistical techniques, which are the median and mean based techniques, were used to examine the possible relationship between the Earth Movement and the variation of the fcF2 in the ionosphere. In this research, five cases of strong Earthquakes in Indonesia with Ritcher scale from 6.4 to 9.1 for the year 2004 and 2007 were chosen. However, only two cases are in good agreement with the results obtained from the previous research that was done in India. Both Earthquakes occurred at off west coast of Northern Sumatra (M=9.1) and Java (M=7.5). The results showed that fcF2 are reducing 23 to 26 days prior to the Earthquake occurred at the off west coast of Northern Sumatra and within 5 days prior to the Java Earthquake. Data fitting was done to the ionospheric perturbations (i.e. fc) before and after the Earthquake by using the mathematical equations from Matlab. The fittings show better approximation with the mathematical equations in the 5th order. Nevertheless, those equations were not good enough to be an analytical mathematical model to represent the precursor for any Earthquake event because the ionosphere varies diurnally.
Daniel Jean Stanley - One of the best experts on this subject based on the ideXlab platform.
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Archaeology to refine Holocene subsidence rates along the Nile delta margin, Egypt
Geology, 1993Co-Authors: Andrew G. Warne, Daniel Jean StanleyAbstract:Archaeological material and sites in the northern Nile delta record rates of land subsidence that are higher than those derived from radiocarbon-dated subsurface sediments. Reassessment of subsidence-rate calculations reveals that previous subsidence measurements of 1-5 mm/yr for the delta are minimum rates, because sediment reworking can result in radiocarbon-dated core ages that are older than the ages of final burial. Integration of archaeological and geologic subsurface data is essential for accurate age determinations, differentiation of sub-sidence from sea-level rise, and more precise calculation of vertical Earth Movement. Application herein of archaeological data to geological problems helps to refine subsidence-rate measurements between the flexure zone (landward margin of the Holocene Nile delta depocenter) and the coast.
Sara Rivas - One of the best experts on this subject based on the ideXlab platform.
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The landslide hazard and human vulnerability in La Paz City, Bolivia
The Geographical Journal, 2005Co-Authors: Greg O'hare, Sara RivasAbstract:Landslides in the city of La Paz, Bolivia are complex in space and time. Their distribution within the city is differentiated by geographical variations in slope gradient, the nature of overlying surface deposits, and drainage density patterns. When mapped, the distribution of the most landslide-prone locations in the city coincides with the most mobile surface deposits on the higher and steeper slopes of the city. The timing of landslides is triggered when slope materials become saturated with moisture by rainfall, stream water, water seepage from high surrounding water tables, and from domestic sources. Landslide frequencies over the last 40 years show the role of inter-annual variations in summer rainfalls, especially the late summer period (Jan–Mar), and rising water tables connected to Lake Titicaca. Associations with ENSO events, both warm (El Nino) and cold (La Nina), prove negative, pointing to the importance of moisture sources from the north, south and east (Amazon) but not from the west (Pacific). The most vulnerable group exposed to the landslide hazard comprise the inhabitants of the self-built informal housing areas who occupy the more elevated steeper slopes of the northern part of the city. But societal vulnerability to Earth Movement in the city is widespread and interconnected. Higher income groups in the southern part of the city are affected by slower, if less dramatic, forms of land failure, and rich housing in downstream areas of the city are impacted by flash flooding encouraged by deforestation on the northern hill slopes where the poor live. Two case studies highlight the vulnerability and plight of the inhabitants of the self-built settlements in the aftermath of a major landslide, and a brief discussion of hazard mitigation and the importance of building hazard resilient communities concludes the paper.
Andrew G. Warne - One of the best experts on this subject based on the ideXlab platform.
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Archaeology to refine Holocene subsidence rates along the Nile delta margin, Egypt
Geology, 1993Co-Authors: Andrew G. Warne, Daniel Jean StanleyAbstract:Archaeological material and sites in the northern Nile delta record rates of land subsidence that are higher than those derived from radiocarbon-dated subsurface sediments. Reassessment of subsidence-rate calculations reveals that previous subsidence measurements of 1-5 mm/yr for the delta are minimum rates, because sediment reworking can result in radiocarbon-dated core ages that are older than the ages of final burial. Integration of archaeological and geologic subsurface data is essential for accurate age determinations, differentiation of sub-sidence from sea-level rise, and more precise calculation of vertical Earth Movement. Application herein of archaeological data to geological problems helps to refine subsidence-rate measurements between the flexure zone (landward margin of the Holocene Nile delta depocenter) and the coast.
Greg O'hare - One of the best experts on this subject based on the ideXlab platform.
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The landslide hazard and human vulnerability in La Paz City, Bolivia
The Geographical Journal, 2005Co-Authors: Greg O'hare, Sara RivasAbstract:Landslides in the city of La Paz, Bolivia are complex in space and time. Their distribution within the city is differentiated by geographical variations in slope gradient, the nature of overlying surface deposits, and drainage density patterns. When mapped, the distribution of the most landslide-prone locations in the city coincides with the most mobile surface deposits on the higher and steeper slopes of the city. The timing of landslides is triggered when slope materials become saturated with moisture by rainfall, stream water, water seepage from high surrounding water tables, and from domestic sources. Landslide frequencies over the last 40 years show the role of inter-annual variations in summer rainfalls, especially the late summer period (Jan–Mar), and rising water tables connected to Lake Titicaca. Associations with ENSO events, both warm (El Nino) and cold (La Nina), prove negative, pointing to the importance of moisture sources from the north, south and east (Amazon) but not from the west (Pacific). The most vulnerable group exposed to the landslide hazard comprise the inhabitants of the self-built informal housing areas who occupy the more elevated steeper slopes of the northern part of the city. But societal vulnerability to Earth Movement in the city is widespread and interconnected. Higher income groups in the southern part of the city are affected by slower, if less dramatic, forms of land failure, and rich housing in downstream areas of the city are impacted by flash flooding encouraged by deforestation on the northern hill slopes where the poor live. Two case studies highlight the vulnerability and plight of the inhabitants of the self-built settlements in the aftermath of a major landslide, and a brief discussion of hazard mitigation and the importance of building hazard resilient communities concludes the paper.
