著者

Toshihiko HASHIDA Kunihiko SHIMAZAKI

出版者

The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.35, no.5, pp.367-379, 1987 (Released:2009-04-30)

参考文献数

16

被引用文献数

2 3

---

Predictions of seismic intensities are attempted based on a three-dimensional attenuation structure and amplifying factors at stations obtained in the previous study for the Tohoku district, Japan. An empirical relation between `earthquake size' related to the intensity and JMA magnitude MJ is also used. The first prediction is to map spatial distribution of the minimum magnitude MJ of an earthquake which causes intensity 5 at a specific JMA station. The result shows that the effects of regional variation of attenuation and local site condition at the station are important in assessing the seismic hazard. Another attempt is made to predict an annual number of felt earthquakes at each JMA station based on the JMA earthquake catalogue for a period from 1963 to 1984. A comparison of predicted number with the observed one shows a good coincidence between them for each year. This may suggest that the proposed method can successfully predict intensities. However, a comparison of the predicted cumulative number for each intensity grade with the observed one shows that the cumulative numbers for intensities 2, 3, and 4 are underestimated by the proposed method. This result may suggest a nonlinearity between the JMA intensity scale and the logarithm of acceleration, which has been suggested by other evidences.

著者

Hiroshi Katao Naoki Maeda Yoshihiro Hiramatsu Yoshihisa Iio Setsuro Nakao

出版者

The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.45, no.2, pp.105-119, 1997 (Released:2009-04-30)

参考文献数

11

被引用文献数

42 49

---

Earthquake focal mechanisms before and after the 1995 Hyogo-ken Nanbu earthquake have been investigated using seismic records from regional seismic networks. Before the mainshock, seismicity was very active at the Tamba Plateau, a neighboring area of the Hyogo-ken Nanbu earthquake rupture zone. In contrast, the seismicity along the Hyogo-ken Nanbu earthquake rupture zone was not so active. Most earthquakes in these regions had source mechanisms of E-W compression and were of the strike-slip or reverse-fault type. Most aftershocks along the Hyogo-ken Nanbu earthquake rupture zone have strike-slip solutions with P-axis in the E-W or ESE-WNW direction, which is compatible with the trend of aftershock distribution and the strike of active faults the same as the mainshock mechanism. Simultaneously, many other aftershocks were of the reverse-fault type with E-W compression. This area is still controlled by the regional stress field of E-W compression observed before the mainshock. Although, we could find various types of mechanisms in the aftershock sequence, some normal fault-type events were also observed in the mainshock rupture zone. We could find events of SE-NW compression, and this direction is nearly perpendicular to the trend of the mainshock rupture zone. Some aftershocks that occurred near the epicenter of the mainshock had solutions of N-S compression. The geometry of the active fault systems and/or local stress change induced by the mainshock may cause these complex features of focal mechanisms. After the mainshock, the focal mechanisms of earthquakes in the Tamba Plateau were approximately E-W compressional; the same as that before the mainshock.

著者

H. HONDA

出版者

The Seismological Society of Japan, The Volcanological Society of Japan , The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.10, no.2, pp.1-97, 1962 (Released:2009-04-30)

参考文献数

265

被引用文献数

33 62

著者

Tokuji UTSU

出版者

The Seismological Society of Japan, The Volcanological Society of Japan , The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.14, no.2, pp.37-40, 1966 (Released:2009-04-30)

参考文献数

6

被引用文献数

68 157

---

The probability density function for the value of b in the formula logn(M)=a-bM estimated by the author's method has been obtained in an exact form. This function leads to a simple method to test the statistical significance of the difference between two b-values. Application of this method to SUYEHIRO'S data on foreshocks and aftershocks of the great Chilean earthquake of 1960 indicates a significant difference in b-value between the foreshocks and the aftershocks at the 98% confidence level.

著者

H. S. VIRK S. L. KOUL

出版者

The Seismological Society of Japan, The Volcanological Society of Japan , The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.25, no.2, pp.177-186, 1977 (Released:2009-04-30)

参考文献数

17

被引用文献数

12 12 12

---

The fossil fission track technique has been used for dating Himalayan muscovites of Kathmandu Valley, Nepal. The mean ages obtained for different locations range from 2.5±0.6m.y. to 23±3.3m.y. The uranium concentration has been estimated to be 10-10 atom/atom. The experimental results confirm that the Himalayan orogeny belongs to the Tertiary era.

著者

Masanori SAITO

出版者

The Seismological Society of Japan, The Volcanological Society of Japan , The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.22, no.3, pp.313-324, 1974 (Released:2009-04-30)

参考文献数

2

被引用文献数

4 5

---

The use of Hilbert transform is essential when we are dealing with bandwidth limited signals and causal functions. However, the Hilbert transform is originally defined for functions of continuous arguments and is not of immediate use for discrete (sampled) functions which are the common form of data today. In this paper we propose two kinds of 'discrete Hilbert transforms'; one is defined on the discrete time domain and the other on the frequency domain of sampled functions. It will be shown that the essential properties of the conventional Hilbert transform are conserved in the new definitions.