Recent progress of seismic observation networks in Japan —Hi-net, F-net, K-NET and KiK-net—

Strong motions observed by K-NET and KiK-net during the 2016 Kumamoto earthquake sequence

The nationwide strong-motion seismograph network of K-NET and KiK-net in Japan successfully recorded the strong ground motions of the 2016 Kumamoto earthquake sequence, which show the several notable characteristics. For the first large earthquake with a JMA magnitude of 6.5 (21:26, April 14, 2016, JST), the large strong motions are concentrated near the epicenter and the strong-motion attenuat...

Estimating near-surface shear wave velocities in Japan by applying seismic interferometry to KiK-net data

We estimate shear-wave velocities in the shallow subsurface throughout Japan by applying seismic interferometry to the data recorded with KiK-net, a strongmotion network in Japan. Each KiK-net station has two receivers; one receiver on the surface and the other in a borehole. By using seismic interferometry, we extract the shear wave that propagates between these two receivers. Applying this me...

Net Neutrality vs. Net Neutering

On-net and off-net pricing on asymmetric telecommunications networks

The differential between on-net and off-net prices, for example on mobile telephony networks, is hotly debated between telecoms operators and regulators. Small operators contend that their competitors’ high off-net prices are anticompetitive. We show that if the utility of receiving calls is taken into account, the equilibrium pricing structures will indeed depend on firms’ market shares. Large...

Customer Net A Customer Net D Customer Net C Customer Net

As IP technologies providing both tremendous capacity and the ability to establish dynamic secure associations between endpoints emerge, Virtual Private Networks (VPNs) are going through dramatic growth. The number of endpoints per VPN is growing and the communication pattern between endpoints is becoming increasingly hard to forecast. Consequently , users are demanding dependable, dynamic con-...