• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2009년도 정기 학술발표대회
• /
• pp.43-50
• /
• 2009

Strong ground motion attenuation relationship represents a comprehensive trend of ground shakings at sites with distances from the source, geology, local soil conditions, and others. It is necessary to develop an attenuation relationship with careful considerations of characteristics of the target area for reliable seismic hazard/risk assessments. In the study, observed ground motions from the January 2007 magnitude 4.9 Odaesan earthquake and the events occurring in the Gyeongsang provinces are compared with the previously proposed ground attenuation relationships in the Korean Peninsula to select most appropriate one. In the meantime, a few strong ground motion attenuation relationships are proposed and introduced in HAZUS, which have been designed for the Western United States and the Central and Eastern United States. The selected relationship from the ones for the Korean Peninsula has been compared with attenuation relationships available in HAZUS. Then, the attenuation relation for the Western United States proposed by Sadigh et al. (1997) for the Site Class B has been selected for this study. Reliability of the assessment will be improved by using an appropriate attenuation relation. It has been used for the earthquake loss estimation of the Gyeongju area located in southeast Korea using the deterministic method in HAZUS with a scenario earthquake (M=6.7). Our preliminary estimates show 15.6% damage of houses, shelter needs for about three thousands residents, and 75 life losses in the study area for the scenario events occurring at 2 A.M. Approximately 96% of hospitals will be in normal operation in 24 hours from the proposed event. Losses related to houses will be more than 114 million US dollars. Application of the improved methodology for loss estimation in Korea will help decision makers for planning disaster responses and hazard mitigation.

• 한국지반공학회논문집
• /
• 제21권6호
• /
• pp.101-115
• /
• 2005

국내 내륙의 지형 및 지질 특성을 대표하는 두 지역인 경주와 홍성을 대상으로 전단파 속도$(V_s)$ 획득 목적의 현장 탄성파 시험을 포함한 다양한 지반 조사를 실시하여 지반 특성을 평가하고, 이를 토대로 등가 선형 및 비선형 기법의 부지 응답 해석을 수행하였다. 현행 국내 내진 설계의 근간인 미국 서부 지역과의 지반 특성 비교 결왔 국내 내륙 지역의 기반암 심도는 매우 얕고 강성은 다소 컸다. 지반 분류 기준인 심도 30m까지의 평균 전단파 속도$V_s30$는 대상 지역 내에서 $250\sim650m/s$의 좁은 범위의 분포를 보였고, 그에 따라 대부분의 부지가 C와 D 지반 조건으로 분류되었다. 부지 응답 해석 결과로부터 현행 국내 내진 설계를 위한 단주기 증폭 계수$(F_ㅁ)$는 지반 운동을 과소평가하고 중장주기 증폭계수$(F_v)$는 과대평가하고 있음을 확인하였다. 이에 따라 국내 내륙 지역에 대한 지반 증폭 계수를 재산정하고, 지역적 지반 특성을 고려하여 기존 지반 분류 C 및 D의 세부 분류와 지표면 부근 심도까지의 평균 $V_s$인 $V_s20,\;V_s15,$ 와 $V_s10$의 추가 분류 기준이 적용된 합리적 지반 분류 체계를 제안하였다. 제안된 지반 분류 체계는 현재로서는 예비적인 방안이므로 향후 보완 및 개선이 필요할 것으로 판단된다.

• 한국환경복원기술학회지
• /
• 제22권5호
• /
• pp.1-12
• /
• 2019

It is important to measure the height of trees as an essential element for assessing the forest health in urban areas. Therefore, an automated method that can measure the height of individual tree as a three-dimensional forest information is needed in an extensive and dense forest. Since airborne LiDAR dataset is easy to analyze the tree height(z-coordinate) of forests, studies on individual tree height measurement could be performed as an assessment forest health. Especially in urban forests, that adversely affected by habitat fragmentation and isolation. So this study was analyzed to measure the height of individual trees for assessing the urban forests health, Furthermore to identify environmental factors that affect forest growth. The survey was conducted in the Mt. Bongseo located in Seobuk-gu. Cheonan-si(Middle Chungcheong Province). We segment the individual trees on coniferous by automatic method using the airborne LiDAR dataset of the two periods (year of 2016 and 2017) and to find out individual tree growth. Segmentation of individual trees was performed by using the watershed algorithm and the local maximum, and the tree growth was determined by the difference of the tree height according to the two periods. After we clarify the relationship between the environmental factors affecting the tree growth. The tree growth of Mt. Bongseo was about 20cm for a year, and it was analyzed to be lower than 23.9cm/year of the growth of the dominant species, Pinus rigida. This may have an adverse effect on the growth of isolated urban forests. It also determined different trees growth according to age, diameter and density class in the stock map, effective soil depth and drainage grade in the soil map. There was a statistically significant positive correlation between the distance to the road and the solar radiation as an environmental factor affecting the tree growth. Since there is less correlation, it is necessary to determine other influencing factors affecting tree growth in urban forests besides anthropogenic influences. This study is the first data for the analysis of segmentation and the growth of the individual tree, and it can be used as a scientific data of the urban forest health assessment and management.