Observation for regional crustal deformation by means of the Global Positioning System (GPS) has been carried out since 1988 at five permanent stations and some additional ones, as well, in the Tohoku district. Recent results show stable baseline solutions and low strain rates, about 0.1 ppm/yr or less for every baselines to reveal its potential to be effective instruments to obtain the intraplate deformations due to the interaction between the Pacific and North American plates. Two period of Selective Availability (S/A) were encountered in our observation. The former gave much errorneous results, while its effect in the other was not obvious. ROCKEN and MEERTENS  found in their experiments that S/A with δ-process, which dither satellite clocks, does not affect baseline solutions even for baselines with longer than 100 km and our results are consistent with their conclusion.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)