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We modeled the vertical deformation detected from a leveling survey in Jigokudani valley, Tateyama volcano, central Japan. In Jigokudani valley, uplift of 4 cm/year was previously detected during the period from 2007 to 2010 by interferometric synthetic aperture radar (InSAR). To confirm whether this inflation has continued to present day, we have conducted leveling surveys in Jigokudani valley since 2015. Most bench marks showed a subsidence of up to 5.6 cm during the 4-year period from October 2016 to September 2020, while a bench mark located at the center of the leveling route uniquely showed an uplift of 1.6 cm. We applied a dislocation source model to the deformation using a grid search method. A crack with a length of 650 m, a width of 425 m, a strike of N18 degrees E and a dip of 67 degrees is located at a depth of 50 m near the center of Jigokudani valley (Koya jigoku and the new fumarolic area) where higher activity has been observed recently. Closing of the crack of 59 cm yields a volume decrease of 163,000 m(3). The closing direction of the crack is parallel to the line of old explosion craters (Mikurigaike and Midorigaike ponds) and corresponds to the current maximum compressive stress field in the region of the Hida Mountains, including Tateyama volcano. The deformation source of the previous period from 2007 to 2010 detected from InSAR was estimated to be at a depth of 50 m and a gas chamber was correspondingly found in an audio-frequency magnetotelluric (AMT) survey. The AMT survey also revealed that thermal fluid is accumulating from a magma chamber and the location of our crack is similar to uppermost part of the thermal fluid path. During the period from 2015 to 2016, the crack opened and the inflation stopped during the next 1 year period from 2016 to 2017. During the period from 2017 to 2020, the crack began closing, probably because of the increase in emissions of volcanic fluid or gas with the formation of a new crater at the western side of J

We modeled the vertical deformation detected from a leveling survey in Jigokudani valley, Tateyama volcano, central Japan. In Jigokudani valley, uplift of 4 cm/year was previously detected during the period from 2007 to 2010 by interferometric synthetic aperture radar (InSAR). To confirm whether this inflation has continued to present day, we have conducted leveling surveys in Jigokudani valley since 2015. Most bench marks showed a subsidence of up to 5.6 cm during the 4-year period from October 2016 to September 2020, while a bench mark located at the center of the leveling route uniquely showed an uplift of 1.6 cm. We applied a dislocation source model to the deformation using a grid search method. A crack with a length of 650 m, a width of 425 m, a strike of N18 degrees E and a dip of 67 degrees is located at a depth of 50 m near the center of Jigokudani valley (Koya jigoku and the new fumarolic area) where higher activity has been observed recently. Closing of the crack of 59 cm yields a volume decrease of 163,000 m(3). The closing direction of the crack is parallel to the line of old explosion craters (Mikurigaike and Midorigaike ponds) and corresponds to the current maximum compressive stress field in the region of the Hida Mountains, including Tateyama volcano. The deformation source of the previous period from 2007 to 2010 detected from InSAR was estimated to be at a depth of 50 m and a gas chamber was correspondingly found in an audio-frequency magnetotelluric (AMT) survey. The AMT survey also revealed that thermal fluid is accumulating from a magma chamber and the location of our crack is similar to uppermost part of the thermal fluid path. During the period from 2015 to 2016, the crack opened and the inflation stopped during the next 1 year period from 2016 to 2017. During the period from 2017 to 2020, the crack began closing, probably because of the increase in emissions of volcanic fluid or gas with the formation of a new crater at the western side of J

We modeled the vertical deformation detected from a leveling survey in Jigokudani valley, Tateyama volcano, central Japan. In Jigokudani valley, uplift of 4 cm/year was previously detected during the period from 2007 to 2010 by interferometric synthetic aperture radar (InSAR). To confirm whether this inflation has continued to present day, we have conducted leveling surveys in Jigokudani valley since 2015. Most bench marks showed a subsidence of up to 5.6 cm during the 4-year period from October 2016 to September 2020, while a bench mark located at the center of the leveling route uniquely showed an uplift of 1.6 cm. We applied a dislocation source model to the deformation using a grid search method. A crack with a length of 650 m, a width of 425 m, a strike of N18 degrees E and a dip of 67 degrees is located at a depth of 50 m near the center of Jigokudani valley (Koya jigoku and the new fumarolic area) where higher activity has been observed recently. Closing of the crack of 59 cm yields a volume decrease of 163,000 m(3). The closing direction of the crack is parallel to the line of old explosion craters (Mikurigaike and Midorigaike ponds) and corresponds to the current maximum compressive stress field in the region of the Hida Mountains, including Tateyama volcano. The deformation source of the previous period from 2007 to 2010 detected from InSAR was estimated to be at a depth of 50 m and a gas chamber was correspondingly found in an audio-frequency magnetotelluric (AMT) survey. The AMT survey also revealed that thermal fluid is accumulating from a magma chamber and the location of our crack is similar to uppermost part of the thermal fluid path. During the period from 2015 to 2016, the crack opened and the inflation stopped during the next 1 year period from 2016 to 2017. During the period from 2017 to 2020, the crack began closing, probably because of the increase in emissions of volcanic fluid or gas with the formation of a new crater at the western side of J

The development of new methods for estimating precise forest structure parameters is essential for the quantitative evaluation of forest resources. Conventional use of satellite image data, increasing use of terrestrial laser scanning (TLS), and emerging trends in the use of unmanned aerial systems (UASs) highlight the importance of modern technologies in the realm of forest observation. Each technology has different advantages, and this work seeks to incorporate multiple satellite, TLS- and UAS-based remote sensing data sets to improve the ability to estimate forest structure parameters. In this paper, two regression analysis approaches are considered for the estimation: random forest regression (RFR) and support vector regression (SVR). To collect the dependent variable, in situ measurements of individual tree parameters (tree height and diameter at breast height (DBH)) were taken in a Japanese cypress forest using the nondestructive TLS method, which scans the forest to obtain dense and accurate point clouds under the tree canopy. Based on the TLS data, the stem volume was then computed and treated as ground truth information. Topographic and UAS information was then used to calculate various remotely sensed explanatory variables, such as canopy size, canopy cover, and tree height. Canopy cover and canopy shapes were computed via the orthoimages derived from the UAS and watershed segmentation method, respectively. Tree height was computed by combining the digital surface model (DSM) from the UAS and the digital terrain model (DTM) from the TLS data. Topographic variables were computed from the DTM. The backscattering intensity in the satellite imagery was obtained based on L-band (Advanced Land Observing Satellite-2 (ALOS-2) Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2)) and C-band (Sentinel-1) synthetic aperture radar (SAR). All satellite (10–25 m resolution), TLS (3.4 mm resolution) and UAS (2.3–4.6 cm resolution) data were then combined, and R

Three-dimensional (3D) morphological changes in rocky coasts need to be precisely measured for protecting coastal areas and evaluating the associated sediment dynamics, although volumetric measurements of bedrock erosion in rocky coasts have been limited due to the lack of appropriate measurement methods. Here we carried out repeat surveys of the 3D measurements of a small coastal island using terrestrial laser scanning (TLS) and structure-from-motion (SfM) photogrammetry with an unmanned aerial system (UAS) for 5 years. The UAS-SfM approach measures the entire shape of the island, whereas the TLS measurement enables to obtain more accurate morphological data at a scale of centimeters on the land side. The multitemporal TLS-derived data were first aligned in timeline by the iterative closest point (ICP) method and they were used as positionally correct references. The UAS-SfM data were then aligned to each of the TLS-derived data by ICP to improve its positional accuracy. The changed areas for each period was then extracted from the aligned UAS-derived point clouds and were converted to 3D mesh polygons, enabling a differential volume estimate (DVE). The DVE for each period was revealed to be from 3.1 to 77.2 m(3)/month. These changes are rapid enough to force the coastal bedrock island to disappear in 30 years. The temporal variations in the DVE is roughly associated with those in the frequency of high tidal waves.

Three-dimensional (3D) morphological changes in rocky coasts need to be precisely measured for protecting coastal areas and evaluating the associated sediment dynamics, although volumetric measurements of bedrock erosion in rocky coasts have been limited due to the lack of appropriate measurement methods. Here we carried out repeat surveys of the 3D measurements of a small coastal island using terrestrial laser scanning (TLS) and structure-from-motion (SfM) photogrammetry with an unmanned aerial system (UAS) for 5 years. The UAS-SfM approach measures the entire shape of the island, whereas the TLS measurement enables to obtain more accurate morphological data at a scale of centimeters on the land side. The multitemporal TLS-derived data were first aligned in timeline by the iterative closest point (ICP) method and they were used as positionally correct references. The UAS-SfM data were then aligned to each of the TLS-derived data by ICP to improve its positional accuracy. The changed areas for each period was then extracted from the aligned UAS-derived point clouds and were converted to 3D mesh polygons, enabling a differential volume estimate (DVE). The DVE for each period was revealed to be from 3.1 to 77.2 m(3)/month. These changes are rapid enough to force the coastal bedrock island to disappear in 30 years. The temporal variations in the DVE is roughly associated with those in the frequency of high tidal waves.