We are developing new geophysical instruments,
such as seismometers, gravimeters, and
strainmeters, to search for phenomena in the
interior of the earth, based on laser technology
with high detectability.
In 2016, a 1500-m-long laser strainmeter was
constructed at an underground site in Kamioka
mine, Gifu Pref., Japan. Ground motions with
broad time-scales have been observed with the
strainmeter, such as earth tides and coseismic
crustal deformations. We continue observations
and analyses with the world\’s longest laser
A compact gravimeter of our own development
will be used for monitoring magma motion in
volcanos and may contribute to forecasting
The seismic and gravimetric methods can be
applied also to planetary explorations searching
for interior structure of planets and small
We can obtain geophysical data only after we
start observation with instruments. We believe
a novel geophysical instrument will open up new
knowledge on the earth and the planets.
1. Araya, A., et al., Evaluation of systematic errors in the compact absolute gravimeter TAG-1 for network monitoring of volcanic activities, in IAG Symposia. Springer, Berlin, Heidelberg, 2020. https://doi.org/10.1007/1345_2020_107
2. Araya, A., et al., Design and operation of a 1500-m laser strainmeter installed at an underground site in Kamioka, Japan, Earth, Planets and Space, 69:77, 2017.
3. Araya, A., et al., Development and demonstration of a gravity gradiometer onboard an autonomous underwater vehicle for detecting massive subseafloor deposits, Ocean Engineering, 105, 64-71, 2015.