• Journal of the Korean earth science society
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• v.41 no.5
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• pp.478-489
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• 2020

This study presents an analysis of infrasonic signals from two accidental explosions in Gwangyang city, Jeonnam Province, Korea, on December 24, 2019, recorded at 12 infrasound stations located 151-435 km away. Infrasound propagation refracted at an altitude of ~40 km owing to higher stratospheric wind in the NNW direction, resulting in favorable detection at stations in that direction. However, tropospheric phases were observed at stations located in the NE and E directions from the explosion site because of the strong west wind jet formed at ~10 km. The transmission losses on the propagation path were calculated using the effective sound velocity structure and parabolic equation modeling. Based on the losses, the observed signal amplitudes were corrected, and overpressures were estimated at the reference distance. From the overpressures, the source energy was evaluated through the overpressure-explosive charge relationship. The two explosions were found to have energies equivalent to 14 and 65 kg TNT, respectively. At the first explosion, a flying fragment forced by an explosive shock wave was observed in the air. The energy causing the flying fragment was estimated to be equivalent to 49 kg or less of TNT, obtained from the relationship between the fragment motion and overpressure. Our infrasound propagation modeling is available to constrain the source energy for remote explosions. To enhance the confidence in energy estimations, further studies are required to reflect the uncertainty of the atmospheric structure models on the estimations and to verify the relationships by various ground truth explosions.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.354-364
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• 2019

Sri Lanka is an island nation susceptible to climate-related disasters and extreme weather events. Kurunegala City is the developing capital city of the North-Western Province of Sri Lanka. Changes in rainfall patterns and a steadily increasing annual average temperature amounting to 0.69±0.37℃ were observed in the city area. Generally, urban areas are at risk due to the lack of climate change adaptation provisions incorporated in the development plans. This study was conducted to investigate the characteristics of Krunegala City, Sri Lanka and develop an appropriate climate change adaptation plan for the city. Site investigation and qualitative risk assessment were conducted to devise a plan relevant to the climate change adaptation needs of the city. Qualitative risk analyses revealed that drinking water, water resources, and health and infrastructure risks were among the major concerns in Kurunegala City. Low impact development (LID) technologies were found to be applicable to induce non-point source pollutant reduction, relieve urban heat island phenomenon, and promote sound water circulation systems. These technologies can be effective means of alleviating water shortage and reducing urban temperature. The measures and strategies presented in this study can serve as reference for developing climate change adaptation plans in areas experiencing similar adverse effects of climate change.