JMA
Japan Meteorological Agency
Seismograph‐based observations in Japan by government agencies began in 1884 at the Tokyo Meteorological Observatory (TMO) (Kitahara et al., 2012). The TMO was a predecessor of the Central Meteorological Observatory (CMO), which became the JMA in 1956. Apart from the CMO, meteorological observations were also conducted in each local government. All the observatories initiated by local governments were transferred to the federal government in 1938 and 1939 (Nemoto, 1957) and later became a part of the JMA. Many stations have been relocated multiple times, and some stations were renamed when they were moved to other cities (Hamada, 2000). As a result, there are a total of about 160 stations, including temporary stations. Many earthquakes were recorded at these stations using analog methods, until digital recording started in the 1990s. (Furumura et al., 2020)
Stations
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Location of Japan Meteorological Agency (JMA) stations. The JMA deployed a total of about 160 stations, and we have scanned seismograms at 113 stations so far (denoted by colored triangles). Black squares denote stations for which images of seismograms are not included in the database. Original seismograms no longer exist from 10 stations where seismic observations were stopped before 1950s. From Furumura et al., (2020)
Instrumentation
| Class | Seismograph | Approximate Magnification |
|---|---|---|
| S | Bracket seismograph+, Gray–Milne–Ewing seismograph+, Omori strong‐motion seismograph, Imamura strong‐motion seismograph, mechanical strong‐motion seismograph, and so forth. | 1–10 |
| P | Omori seismograph, Omori tremometer, portable tremometer, 54‐type mechanical seismograph, and so forth. | 20–50 |
| W | Wiechert seismograph, Mainka seismograph, JMA‐59‐type electromagnetic seismograph, JMA‐61‐type electromagnetic seismograph, and so forth. | 100–200 |
| A | Ishimoto‐type seismographs, JMA‐56‐type seismograph, 76‐type short‐period electromagnetic seismograph, 88‐type short‐period electromagnetic seismograph, and so forth. | 300 or more |
| X | Unknown | – |
JMA, Japan Meteorological Agency.
+Triggered type.
From Furumura et al., (2020)
Recording Medium
smoked paper
ink
Data Availability
Records recorded at 113 stations can be viewed and downloaded from the HERP website as JPEG2000 files.
The original images were saved as TIFF format files with 8 bit color.
| station | no. available | format | dpi | color |
|---|---|---|---|---|
| 185,000 | JPEG2000 | 400-500 |
The number of digital image files of scanned seismograms in 5 yr intervals. Seismographs are classified into five groups by their magnification as shown in the above table. From Furumura et al., (2020)
See supplement to Furumura et al., (2020) for the number of scanned images for each station per year.
The copyright of all images in the HERP data retrieval system of JMA analog seismograms is retained by ADEP, MEXT, and JMA. Those who use any part of these scanned images for their research, and those who publish a paper with the data from this system should mention the copyright based on the description on the top page of the retrieval system.
Any commercial use of these images is not allowed.
Contact
For more information about this collection, please contact:
References
Furumura, Mitsuko; Koji Iwasa, Yasunori Suzuki, Tomotsugu Demachi, Takeo Ishibe, Ritsuko S. Matsu’ura (2020). Data Retrieval System of JMA Analog Seismograms in the Headquarters for Earthquake Research Promotion of the Japanese Government. Seismological Research Letters; 91 (3): 1403–1412. doi: https://doi.org/10.1785/0220190303
HERP Data Retrieval System of the JMA Analog Seismograms. 2022 http://www.susu.adep.or.jp/. last accessed 2 February 2022.
Kitahara I., Matsu’ura R. S., and Kimura R. (2012). Nihon Rekishi Saigaishi Jiten (Encyclopedia of Historical Disasters in Japan) , Yoshikawa Kobunkan, Tokyo, Japan, 892 pp. (in Japanese).
Nemoto J. (1957). Brief history of Meteorological Society of Japan in the wartime, in Short History of the Meteorological Society of Japan in Commemoration of the 75th Anniversary , Meteorological Society of Japan, Tokyo, Japan, 69 pp. (in Japanese).