The most powerful Tohoku–Oki(TO) earthquake that occurred in Japan on 11 March 2011 affected Japan as well as South Korea. In the current study, we investigated contemporary geodetic deformation inside South Korea be...The most powerful Tohoku–Oki(TO) earthquake that occurred in Japan on 11 March 2011 affected Japan as well as South Korea. In the current study, we investigated contemporary geodetic deformation inside South Korea before and after the TO earthquake using Global Navigation Satellite System(GNSS) measurements from 01 January 2008 to 31 December 2017. Measured velocities of GNSS sites are modeled by Auto-regressive moving average(ARMA) method to analyze the long-term GNSS time-series variation and to investigate the secular tectonic crustal deformation. We found that the maximum co-seismic displacements during the TO earthquake reached up to 36.82 ± 0.21 mm in the east and 5.90 ± 0.08 mm in the north directions. The geometric model of the co-seismic thrust surface was characterized by a rectangular plane with a dip of 12.0° and strike 200°. The thrust is situated at 25 km hypocenter depth, with an area roughly ~470 km long and ~120 km wide. The seismicity pattern after the earthquake indicated that the compressional strain started to be replaced by the extensional strain during the post TO earthquake period from 2011 to 2014. Further, the strain became predominantly extensional during the period 2015 to 2017, revealing an effective rotational change that occurred inside the Korean Peninsula.展开更多
Since the last assessment of ecological zones of Sudan conducted in 1958 by Harrison and Jackson, the vegetation types, cover, and its distribution have undergone remarkable changes;this change occurs in most of the p...Since the last assessment of ecological zones of Sudan conducted in 1958 by Harrison and Jackson, the vegetation types, cover, and its distribution have undergone remarkable changes;this change occurs in most of the predominant ecological zones, particularly those which are currently affected by environmental degradation and desertification due to climate change impact on vegetation cover and rainfall amounts and its distribution. In addition, during the last five decades, Sudan has suffered from environmental devastating changes that have undermined food security, which is strongly linked to human displacement and related conflicts. In this study, SPOTVEG NDVI data acquired between 2000 and 2010 were used to produce a vegetation cover map, which was integrated with rainfall map to produce updated ecological zones map for the study area in 2010. This map was compared to that produced in 1958 to analyze the change during the last five decades. The obtained results showed drastic change concerning different ecological zones. The desert class increased by 11%. The Semi-Desert class decreased by approximately 13.2%. The woodland savannah class increased by 6.8%. While, the Mountain vegetation areas decreased approximately by 3%. Finally, the wetland areas completely disappeared in 2010. These results show that during the period 1958-2010, climate change impact increased desertification process, destroyed ecological zones, especially wetland, as well the ecosystems diversity in Central Sudan.展开更多
基金supported by Inha University Research Grant(INHA-61597)。
文摘The most powerful Tohoku–Oki(TO) earthquake that occurred in Japan on 11 March 2011 affected Japan as well as South Korea. In the current study, we investigated contemporary geodetic deformation inside South Korea before and after the TO earthquake using Global Navigation Satellite System(GNSS) measurements from 01 January 2008 to 31 December 2017. Measured velocities of GNSS sites are modeled by Auto-regressive moving average(ARMA) method to analyze the long-term GNSS time-series variation and to investigate the secular tectonic crustal deformation. We found that the maximum co-seismic displacements during the TO earthquake reached up to 36.82 ± 0.21 mm in the east and 5.90 ± 0.08 mm in the north directions. The geometric model of the co-seismic thrust surface was characterized by a rectangular plane with a dip of 12.0° and strike 200°. The thrust is situated at 25 km hypocenter depth, with an area roughly ~470 km long and ~120 km wide. The seismicity pattern after the earthquake indicated that the compressional strain started to be replaced by the extensional strain during the post TO earthquake period from 2011 to 2014. Further, the strain became predominantly extensional during the period 2015 to 2017, revealing an effective rotational change that occurred inside the Korean Peninsula.
文摘Since the last assessment of ecological zones of Sudan conducted in 1958 by Harrison and Jackson, the vegetation types, cover, and its distribution have undergone remarkable changes;this change occurs in most of the predominant ecological zones, particularly those which are currently affected by environmental degradation and desertification due to climate change impact on vegetation cover and rainfall amounts and its distribution. In addition, during the last five decades, Sudan has suffered from environmental devastating changes that have undermined food security, which is strongly linked to human displacement and related conflicts. In this study, SPOTVEG NDVI data acquired between 2000 and 2010 were used to produce a vegetation cover map, which was integrated with rainfall map to produce updated ecological zones map for the study area in 2010. This map was compared to that produced in 1958 to analyze the change during the last five decades. The obtained results showed drastic change concerning different ecological zones. The desert class increased by 11%. The Semi-Desert class decreased by approximately 13.2%. The woodland savannah class increased by 6.8%. While, the Mountain vegetation areas decreased approximately by 3%. Finally, the wetland areas completely disappeared in 2010. These results show that during the period 1958-2010, climate change impact increased desertification process, destroyed ecological zones, especially wetland, as well the ecosystems diversity in Central Sudan.
