- 公益社団法人 日本地震学会
- 地震 第2輯 (ISSN:00371114)
- vol.72, pp.35-41, 2019-06-05 (Released:2019-08-03)
Spatial distribution of seismicity has hitherto been visualized on two-dimensional maps and vertical cross-sections along certain lines so far. Owing to the advances in technology, we have developed a mobile application for iPhone and iPad devices, which can display the seismicity of Japan in three-dimensional (3D) view. Each hypocenter is plotted as a 3D spherical object whose color and size represented its depth and magnitude, respectively. The geometry of the Philippine Sea Plate and the Pacific Plate can be plotted as 3D polygons with the hypocenters, simultaneously. In addition to those plate boundaries, the topography of Japan and the ocean bathymetry around it are also plotted as a 3D polygon. The 3D image of the hypocenters and plate geometries helps users to perceive intuitively the spatial distribution of earthquakes such as that many earthquakes occur along the subducting plates. Moreover, the spatiotemporal distribution of seismicity can be seen by the time-lapse animation of hypocenters. The hypocenter catalog can be downloaded through the Internet by using the account of NIED MOWLAS. More than one month’s earthquakes (18,000 events) can be displayed smoothly.