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Volume 32 (1986)
- Issue 4 Pages 227-
- Issue 3 Pages 167-
- Issue 2 Pages 89-
- Issue 1 Pages 1-
Volume 32, Issue 4
Displaying 1-8 of 8 articles from this issue
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Yukio HAGIWARA1986 Volume 32 Issue 4 Pages 227-235
Published: March 25, 1987
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSBoundary detection and texture analysis methods in computer picture-processing techniques can be applied to extracting a fault structure from Bouguer anomaly map . This paper aims at finding effects of San Andreas and Garlock fault systems on the gravity field of California, U. S. A., by using these methods. We conclude that conventionally used two-dimensional running average and second deivatives methods are most effective for extracting fault-related gravity trends.View full abstractDownload PDF (4975K) -
Tsutomu SAITO, Nobuo ISAWA1986 Volume 32 Issue 4 Pages 236-247
Published: March 25, 1987
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSA hand-held programable computer (SHARP PC 1501 with EC-150) has the function of both chronometer and chronograph as well as that of calculator. We construct a program for the computer, by which solar observation and its reduction can be performed for determining longitude and latitude of stations without the use of solar ephemeris. We also discuss the implication of the outputs. The dump-list of the program is shown in BASIC.View full abstractDownload PDF (726K) -
-0.1 nT Resolution, ROM memory and Acoustic Release-Jiro SEGAWA, Yozo HAMANO, Takesi YUKUTAKE, Hisashi UTADA, Hiroaki TOU1986 Volume 32 Issue 4 Pages 248-273
Published: March 25, 1987
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSBSTRACT A sea floor magnetometer Model OBM-S4 with a 0.1 nT resolution was designed, manufactured and tested. This meter has so far been used for the actual measurements at the sea floor several times, having proved to be a meter with excellent performance. This meter is characterized by the small size and light weight as well as free fall installation and acoustically controlled recovery.View full abstractDownload PDF (3796K) -
Teruki MIYAZAKI, Kiyokazu NISHIMURA1986 Volume 32 Issue 4 Pages 274-281
Published: March 25, 1987
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSAn acoustic transponder navigation system is used for positioning of a deep-tow system. The navigation system utilizes travel-time of acoustic pulse through the direct path to know a distance, because the direct wave does not decay a lot and is observed as the first arrival. A wave pulse propagating another path is, however, detected at the surface. The experiment carried out during the test operation of a deep-tow system shows the following results: (1) a relay transponder responds to interrogation pulses propagating through a direct path and another path, (2) response pulses propagating through a dirct path are observed at the surface, and (3) a reflected pulse of the response at the surface is detected at the deep-tow system. This evidence tells us that exhaustion of a battery of a transponder must be estimated based on multi-response to an interrogation, and the following possible use: (1) as an inverted echo sounder, and (2) positioning of a deep-tow system using multiresponse.View full abstractDownload PDF (5331K) -
Yoichiro FUJII, Koji NAKANO1986 Volume 32 Issue 4 Pages 282-289
Published: March 25, 1987
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDifferential scale factor method in EDM was first introduced by WHITE (1973), and succeeding study was made by TANAKA (1978) in Japan. The present authors added to these studies a formula for evaluating the variance-covariance matrix of adjusted side-length, and made a field test observation in Iwase, a town in the Ibaraki Prefecture, Japan, The followings are main conclusions: (1) When the observations are carried out even under unstable atmospheric con-ditions, we can obtain reliable values that are very close to the one under normal atmospheric condition, (2) Standard deviations of the adjusted side-lengths are within range of several milimeters, and never exceed ten millimeters, (3) Some times we are obliged to get systematically, deviated values as compared with normal values, (4) This method is more suitable to estimate crustal shear strain, because under this method figure is more exactly determined than the size of the geodetic figure.View full abstractDownload PDF (677K) -
Masahiro KOSUGA, Hitomi IKEDA, Yoshitada KAMAZUKA, Hiroshi SATO1986 Volume 32 Issue 4 Pages 290-302
Published: March 25, 1987
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSA fault model of the 1983 Nihonkai-chubu (Japan Sea) earthquake (MJMA 7.7) was investigated on the basis of aftershock distributions, crustal deformation, and tsunami data. Since the earthquake took place under the sea off the coast of northwestern Tohoku District, there are a few land observation of crustal movement near the source area. We, therefore, have estimated the static fault parameters by comparing the wave form of observed tsunami with that of calculated from the static fault model. Trial fault parameters were derived from seismic data: focal mechanism solutions, seismic moment, and aftershock distributions with reference to the rupture process of the main shock. Our model was characterized by three fault planes trending NNE-SSW in the southern and the middle parts and NNW-SSE in the northern part, and by their low dipangle of 25°. The tsunami wave form was simulated numerically by a finite difference method. The fault model derived from seismic data reasonably explains the geodetic data and tsunamis. The calculated vertical deformation of land was consistent with the observed subsidence of 30-40 cm at Kyuroku island situated near the source area, and those of a few centimeters at Oga peninsula and Fukaura. The tsunami wave form observed at tide-gage stations along the coast of the Japan Sea was well simulated by our model as well as the model with higher dip angle. The data of strain step observed by extensometers installed in northern Japan support the low angle thrust event.View full abstractDownload PDF (1240K) -
Masaki MURAKAMI, Yoshiro NAKAHORI1986 Volume 32 Issue 4 Pages 303-309
Published: March 25, 1987
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSGeographical Survey Institute has conducted absolute gravity measurements at foursites in Japan since 1982. The instrument used in these measurements is a Sakuma-type transportable absolute gravimeter, which adopts a symmetrical free rise-and-fall method. Gravity values were successfully determined with uncertainties of less than 0.01 mgal .View full abstractDownload PDF (625K) -
Torao TANAKA1986 Volume 32 Issue 4 Pages 310-313
Published: March 25, 1987
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (437K)
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