Earthquake and tsunami impact
Satellite(s)ASTER (Advanced Spaceborne Thermal Emission and Reflection radiometer), ALOS AVNIR-2 (Advanced Land Observing Satellite, Advanced Visible and Near-Infrared Radiometer type 2), and Sentinel-2. | Monitoring elementLand surface reflectance, SAR backscatter. |
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Description techniqueNguyen Hao and Takewaka (2021) used Normalized Difference Water Index (NDWI) to distinguish water from land. The land-sea boundary was delineated using isocluster unsupervised classification. | Accuracy / ResolutionSpatial resolution: 10-15 m. |
Case studyNguyen Hao and Takewaka (2021) assessed the influence of the Great East Japan Earthquake (which occurred on 11 March 2011) on the shoreline of the northern Ibaraki Coast. | |
BenefitsThe method demonstrated a fairly good agreement between the survey results and shoreline position within the scatter range of spatial resolution of satellite images. | Limitations
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Applicability for NorthlandYes. Limitations could come from the availability of good quality imagery at the time of a potential event. Techniques applying optical data will be limited in coverage and temporal granularity by the persistent cloud cover in the region, particularly during the winter months. Mature cloud-masking techniques are directly available for open access multispectral data (e.g. Landsat and Sentinel-2). When using commercial data, care must be taken to ensure that there is sufficiently cloud free imagery available, as cloud masking is not as mature, and ordering a large volume of imagery to ensure complete cloud free coverage between multiple observations can become cost prohibitive. | |
Publication referencesNguyen Hao Q, Takewaka S. 2021. Shoreline Changes along Northern Ibaraki Coast after the Great East Japan Earthquake of 2011. Remote Sensing. 13(7):1399. |