Average Horizontal Crustal Strain Rates in Japan during Interseismic Period Deduced from Geodetic Surveys. (Part 2).
|
Accession number;99A0960533
|
| Title;Average Horizontal Crustal Strain Rates in Japan during Interseismic Period Deduced from Geodetic Surveys. (Part 2). |
| Author;
ISHIKAWA NORIHIKO
(Kokudochiriin Chirichikakukatsudokense)
HASHIMOTO MANABU
(Kyoto Univ., Disaster Prevention Res. Inst., Center for Earthquake Predict)
|
Journal Title;Journal of the Seismological Society of Japan. Second Series
|
Journal Code:G0931A
|
ISSN:0037-1114
|
|
VOL.52;NO.2;PAGE.299-315(1999)
|
| Figure&Table&Reference;FIG.8, TBL.1, REF.45 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;This is a revision of Hashimoto's (1990) study on average horizontal crustal strain rates in Japan derived from geodetic data collected during the past 100 years. This new study includes Hokkaido since the completion of the latest nationwide trilateration enables us to apply the methods of the previous study and obtain strain rates there. In this method, side lengths of triangulation networks are calculated using adjusted coordinates for different epochs and then the rate of change of each side length is estimated by regression. Finally the principal strain rate in each triangular region is obtained. In order to avoid the effects of large earthquakes or volcanic eruptions, data before or after these events are simply discarded. Unfortunately, due to frequent occurrence of large events in northern Japan, we can use data from only two epochs for most of Hokkaido, which causes large uncertainties in the estimated strain rates. Hokkaido appears to be divided into four provinces according to the characteristics of the horizontal strain rates, although the uncertainties are too large to be definitive. Eastern Hokkaido is characterized by large WNW-ESE contraction. In northern Hokkaido E-W contraction is prevailing, while extension is dominant in southwestern Hokkaido. In other regions the directions of principal axes of strain rates are not noticeably different from those of the previous study. In the Tohoku region, tensile strain rates in a N-S direction are prevailing. A NNW-SSE or NW-SE trending contraction is dominant along the coast from southern Kanto to Shikoku, though it is smaller in the Tokai area and Kii peninsula than in southern Kanto and Shikoku. In the same Shikoku region, there is a remarkable region of NE-SW extension that is as large as contraction. In central Japan, there is a NE-SW trending region of contraction.... (author abst.) |
|
|
|
Related Articles;
|
|
