International Journal of Clean Coal and Energy, 2013, 2, 21-23
doi:10.4236/ijcce.2013.22B005 Published Online May 2013 (http://www.scirp.org/journal/ijcce)
Studying of Deformation Processes by Two-Coordinate
Laser Strainmeter
Grigory I. Dolgikh
V.I. Il'ichev Pacific Oceanological Institute Far Eastern Branch of Russian Academy of Sciences, Vladivostok, Russia
Received 2013
ABSTRACT
The results of experimental data processing of a two-coordinate laser strainmeter are discussed. The two-coordinate
laser strainmeter consists of two laser strainmeters which measuring shoulders are oriented along the lines “North-
South” and “West-East”. Measurement accuracy of the earth's crust microdisplacements of these devices makes 0 to1
nm. Working frequency range is from 0 to 1000 Hz. Processing experimental data the main attention is paid to high
tides, natural oscillations of the Earth, natural oscillations of geoblocks, superficial sea waves. It is established that after
separate earthquakes the natural oscillation s of regional geoblocks are strongly excited. Besid es, it is revealed that qua-
siperiodic fluctuations of crust in the range of periods from 1 to 12 min. are caused by atmospheric processes. Besides,
it is revealed that quasiperiodic oscillations of the earth's crust in the range of p eriods from 1 to 12 minutes are caused
by atmospheric processes.
Keywords: Two-coordinate Laser Strainmeter; High Tides; Earthquakes; Natural Oscillations of the Earth; Natural
Oscillations of Geoblocks; Natural Oscillations of Bays; Sup e rficial and Internal Sea Waves; Quasiperiodic
Oscillations
1. Introduction
Now studying of deformation processes of the Earth car-
ries out with application of the various installations, most
of which has a limited working range of frequencies. The
main direction of these researches is connected with
studying of physics of onset and development of various
catastrophic processes of the Earth: earthquak es, tsunami,
typhoons, waves murderers, eruptions of volcanoes, etc.
Process of preparation of some of them related to the
slow changes of variations stress-deformation field of the
Earth which can't be measured by many installations be-
cause of their limited frequency range. Laser strainmeter
are most suitable for these purposes. They are capable to
measure variations of displacement of the earth’s crust in
the frequency range from 0 to 1000 Hz with a high accu-
racy. It is shown in paper [1] that only application of
spatially separated laser strainmeters will allow to solve a
problem of the short-term prediction of crustal earth-
quakes. And application of laser strainmeters in services
of the prevention tsunami threat, based on a deformation
method for degree assessment of tsunamigenic earth-
quakes [2], will allow not only to determine from 100%
probability tsunami formation after an underwater earth-
quake, but also to calculate its power. To solve these
problems in full is necessary to measure displacement of
the earth's crust in different directions. It is known [3]
that laser strainmeters possess the greatest sensitivity on
the axis. Therefore for determination of size of the dis-
placements coming in different directions, it is necessary
to establish some laser strainmeters of a various orienta-
tion in one point. For this purpose on the range of Pacific
Oceanological Institute Far Eastern Branch Russian
Academy of Sciences (POI FEB RAS) cape Shults a two-
coordinate laser strainmeter was created. It consists of
two laser strainmeters which shoulders are focused on
the “North-South” and “West-East” lines. Besides, this
range is equipped with the Trimble 5700 GPS-receiver,
the three-component broadband seismodetector, a mete-
orological station and a laser nanobarograph. The laser
nanobarograph is capable to carry out measurements of
atmosphere pressure variations with an accuracy of 1
mPa in the frequency range from 0 to 1000 Hz. It is in-
tended for parallel measurement of atmosphere pressure
variations with strainmeters with an assessment of their
contribution to level of microdeformations of the earth’s
crust at the appropriate frequencies.
2. Two-coordinate Laser Strainmeter
As mentioned above, the two-coordinate laser strainmeter
consists of two laser strainmeters with mutually perpen-
dicular working shoulders. The first laser strainmeter
with a shoulder length of 52.5 m, focused on the North-

G. I. DOLGIKH
22
South line is created on the basis of Michelson interfer-
ometer of unequal-arm type and helium-neon laser of
company Neoark (Japan) which frequency stability is at
the level of 10-12 [4]. This laser strainmeter is located in
the underground hydroheat-isolated room at a depth of 3
- 5 m from an earth surface. The second laser strainmeter
with a shoulder length of 17.5 m, focused on the West-
East line, is created on the basis of Michelson interfer-
ometer of unequal-arm type and helium-neon laser of
company MellesGriott, which frequ ency stability is at th e
level of 10–9. The second laser strainmeter with a shoul-
der length of 17.5 m, focused on the West-East line, is
created on the basis of Michelson interferometer of un-
equal-arm type and helium-neon laser of company
Melles Griott, which frequency stability is at the lev el of
10 - 9. This laser strainmeter is located in the under-
ground hydroheatisolated room at a depth of 2 - 4 m from
an earth surface. In 20 m to the east from this laser
strainmeter a three-component broadband seismograph
underground is established underground, and in 30 m to
the south-east – in a specially rebuilt room there is laser
nanobarograph. Antenna GPS-receiver is installed on a
mast near this laboratory room. Strainmeters are at dis-
tance about 70 m from each other. In 50 m from a 17.5-
meter laser strainmeter the meteorological station in-
stalled on the tower, consisting of sensors, measuring
atmosphere pressure variations, wind speed and direction,
air temperature. Data from all installations of a hardware-
software complex come into the laboratory building
where record to the system computer entering into a
network of Far Eastern Branch of the Russian Academy
of Sciences. Further data are processed with application
of modern means of statistical and spectral estimation.
3. Processing and the Analysis of the
Received Results
We will analyse experimental data of laser strainmeters
and the laser nanobarograph, received from 6 to 25 of
April 2012. Considering that the sampling frequency of
data was 1000 Hz, before the analysis of the received
materials their preliminary processing was carried out
with the use of the low-frequency Hamming filter with a
boundary frequency of 1 Hz and averaging 1000. Thus
the intermediate data obtained then were processed by
various methods of spectral and statistical estimation.
Let's analyse the received experimental results for the
purpose of presence the data beginning from tidal com-
ponents to the microseisms excited by wind sea waves of
the Sea of Japan. Figure 1 shows the filtered data by
Hamming high-frequency filter with the boundary period
of 30 hours recordings of laser strainmeters and a laser
nanobarograph.
The obtained experimental data were processed, as a
result spectral characteristics of the series were received,
shown on Figure 1. In low-frequency field in records of
laser strainmeters spectral maxima on the next periods
are marked: 24 h 16 min. 21.3 s, 12 h 08 min. 10.7 s, 8 h
16 min. 29.1 s, 6 h 10 min. 15.6 s, 5 h 16 min. 36 s and 4
h 47 min. 26.3 s. Most of the marked maxima corre-
sponds to tidal harmonics. It is necessary to notice that in
the spectrum of recording of the laser strainmeter similar
harmonics only diurnal and semidiurnal tide are marked.
Other low-frequency spectral components do not match
the spectral components, selected from records of laser
strainmeters.
In the higher-frequency part of the spectrum, along
with selected spheroidal and torsional harmonics of
natural oscillations of the Earth from records of laser
strainmeters after earthquakes of average power, in re-
cords of laser strainmeters and a laser nanobarograph
synchronous quasiharmonious oscillatio ns are marked on
the periods being in period range from 2 to 15 minutes,
which origin can be connected with various sources: at-
mospheric internal gravitatio nal waves, infragravitational
sea waves, internal sea waves, natural oscillations of the
individual water areas. Considering that these oscillatio ns
occur simultaneously on records of laser strainmeter and
a laser nanobarograph, considering an impedance of me-
diums (the atmosphere and upper crust) it is possible to
assume that these disturbances are caused by atmospheric
processes, namely the atmospheric internal gravitational
waves.
Figure 1. Synchronous recor ds of 17,5-mete r laser str ainme ter,
52,5-meter laser strainmeter, laser nanobarograph (top-
down).

G. I. DOLGIKH
23
Figure 2. Synchronous records of a 17,5-meter laser
strainmeter, 52,5-meter laser strainmeter, laser nanobaro-
graph (top-down).
Figure 3. Synchronous records of a 17,5-meter laser strain-
meter and 52,5-meter laser strainmeter (top - down).
The opposite result was received after one of earth-
quakes. It is necessary to notice that the discussed result
further is the extremely rare and is not observed after a
number of earthquakes. This result is that after one of
earthquakes in records of laser strainmeters powerful
low-frequency oscillations were detected with the peri-
ods about 2 minutes 25 s. Similar oscillations were de-
tected in records of a laser nanobarograph. Moreover,
these oscillations occurred to a short time after excite-
ment arrival from the earthquake. It is absolutely clear
that these oscillations are caused by natural oscillations
of geoblocks which caused oscillations of atmospheric
pressure on the corresponding periods, as it was regis-
tered by a laser nanobarograph. Figure 2 shows records
of laser strainmeters and laser nanobarograph at the time
of the earthquake beginning.
In the conclusion we note that laser strainmeters re-
cord good microseisms, caused by sea wind waves at
their interaction with sea bottom at th eir distribution on a
shelf of the decreasing depth. So Figure 3 shows the
synchronous records of two laser strainmeters on which
microseisms are marked with the periods about 8,2 s, the
period is typical for the superficial sea waves, propagat-
ing in the Sea of Japan.
4. Acknowledgements
This work was supported by the Russian Foundation for
Basic Research (RFBR) (grant 12-05-00180-a), RFBR
(11-05-98544-r_vostok_a), Far Eastern Branch (the first
section of competition, the competition “FEB-Taiwan”),
Federal Target Program “Scientific and Scientific and
Pedagogical personnel of innovative Russia” for 2009 -
2013 (projects: “Dynamic characteristics of sea wave
fields of infrasonic range” and “Dynamics and transfor-
mation of sea wind waves”).
REFERENCES
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Prognosis of Crustal Earthquakes by Variations of the
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doi: 10.1134/S1028334X11040118
[2] G. I. Dolgikh, S. G. Dolgikh, S. N. Kovalev, V. A.
Chupin, V. A. Shvets and S. V. Yakovenko, “A Deforma-
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doi: 10.1134/S1028334X07080296
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