• Recommended articles
  • November 12, 2019

[Frontier Letter] Occurrence of F region echoes for the polar cap SuperDARN radars

The quality of global-scale ionospheric plasma circulation maps provided by the SuperDARN radars depends strongly on the number of detected echoes. Over the last decade of relatively low solar activity, the best SuperDARN echo occurrence rates are in the polar cap. Koustov et al. (2019) show that SuperDARN radars in both the North and South hemispheres have similar patterns in echo occurrence over the daily, seasonal, and solar cycles. Many… Read more

  • Recommended articles
  • November 4, 2019

[Frontier Letter] Structural heterogeneity in and around the fold-and-thrust belt of the Hidaka Collision zone, Hokkaido, Japan and its relationship to the aftershock activity of the 2018 Hokkaido Eastern Iburi Earthquake

The 2018 Hokkaido Eastern Iburi Earthquake (M=6.7) occurred at a very deep depth (~37 km) beneath the foreland fold-and-thrust belt of the Hidaka Collision Zone, Hokkaido, Japan. From the previously acquired controlled source seismic data, Iwasaki et al. (2019) revealed the detailed structure beneath this fold-and-thrust belt and its relationship with the aftershock activity of this earthquake. Relocated aftershocks are at depths of 7-45 km with steep geometry, extending to… Read more