Earthquake Research Institute of the University of Tokyo

The Earthquake Research Institute (ERI) of the University of Tokyo has archived analog seismograms recorded on mechanical seismographs operated by ERI and its predecessors between 1881 and 1993. The first observation started in 1880 by J. A. Ewing at Hitotsubashi (Tokyo Imperial University) and continued until 1923. ERI was established in 1925. Seismograms were recorded at various buildings of the University of Tokyo, Tsukuba Observatory, and Wakayama seismological network. The collection includes maregrams and seismograms from a a few foreign networks - Taiwan, Canada, and WWSSN.

Stations

Only select records from the Wakayama Microearthquake Network have been scanned.

See Satake et al. (2020) for a list of stations with curated microfilm records from the University of Tokyo, Tsukuba Observatory, Wakayama Seismological Network, and other locations.

Wakayama Microearthquake Network

The Wakayama microearthquake observatory was established in 1964 at ERI as a network of 10 high‐gain electromagnetic seismographs targeting microearthquakes:

• T=1s, V=12,000–18,000
• pen recording on paper at 4mm/s

Stations with scans available

UD, up–down.

Instrumentation

Wakayama Microearthquake Network

electromagnetic high-gain (short period)

Other

Ewing circular, vertical
Hagiwara
Imamura (strong motion)
Ishimoto (accelerometer)
Omori (seismograph and tremometer)
Press-Ewing
Tremometer
Wiechert horizontal, vertical
Wood-Anderson

Recording Medium

Wakayama Microearthquake Network

ink on paper

Other

ink on paper photographic film
photographic paper
smoked paper

Data Availability

Microfilm

In addition to the original analog seismograms, ERI maintains extensive archives of microfilm data.

ERI
Additional information about the microfilmed seismogram archives at the ERI can be obtained from the Historical Seismogram Search System.

Foreign Seismograms
Access the list (station and date) of foreign seismograms available for:

• Taiwan. Includes station reports, meteorological data, seismic bulletins, and earthquake reports. Seismograms (pdf) of select Taiwan earthquakes recorded in Japan.
• Canada. The Earthquake Research Institute maintains ~1800 rolls of 35 mm films from 23 stations of the Canadian seismograph network between 1982-1989 availability unconfirmed. See also Canada.
• WWSSN. WWSSN microfilms of 167 stations between 1963-1988. See also WWSSN

Mareograms

• Mareogram data

Scanned Images

Images are available for some stations in the Wakayama Microearthquake Network (see list above). This is an ongoing project.

View data at: http://wwweic.eri.u-tokyo.ac.jp/wakayama/

Vectorized Data

A database of digitized historical records and seismogram images for major earthquakes (~35) from 1920-1949 has been constructed. Plans are to make the data available via the National Museum of Nature and Science and ERI (Murotani et al., 2020).

Earthquakes digitized include:

• 1923 Kanto
• 1944 Tonankai
• 1946 Nankai

Contact

For more information about this collection, please contact:

References

Murotani, S., K. Satake, H. Tsuruoka, H. Miyake, T. Sato, T. Hashimoto, and H. Kanamori (2020). A Database of Digitized and Analog Seismograms of Historical Earthquakes in Japan, Seismol. Res. Lett. 91, 1459–1468, doi: https://doi.org/10.1785/0220190287.

Satake, K., H. Tsuruoka, S. Murotani, and K. Tsumura (2020). Analog Seismogram Archives at the Earthquake Research Institute, the University of Tokyo, Seismol. Res. Lett. 91, 1384–1393, doi: 10.1785/0220190281.

Website links above last accessed 3 Feburary 2020.