Earth Magnetic Evolutions over Nusa Tenggara Region from Declination and Inclination Changes on Lombok Geomagnetic Observatory

The 2nd International Conference on
Applied Electromagnetic Technology (AEMT) 2018
Earth Magnetic Fields Evolution over Nusa Tenggara
Region from Declination and Inclination Changes on
Lombok Geomagnetic Observatory
Teti Zubaidah, Bulkis Kanata, Paniran, Misbahuddin, Rosmaliati, Made Sutha Yadnya, Susilawati Riskia
Electrical Engineering Department
University of Mataram
Mataram, Indonesia
[email protected]
Abstract—Earth's magnetic field is a physical quantity that
always changes both spatially and temporally. Its long-term
change is closely related to internal mechanisms within the
Earth's core, whereas changes in the medium-term may be
related to events occurring in the Earth's crust. Continuous
observations at many locations are needed to determine the
magnitude and direction of the Earth's magnetic field. A
geomagnetic observatory is an ideal means for conducting such
observations, whereby its location is required to be very quiet in
order to limit noise and interference (mainly due to human
activities). On the island of Lombok, a geomagnetic observatory
has been established in 2014 and it has produced high quality and
continuous data since 2015. This paper (together with another
paper presented in this conference) presents the results of
observations of the Earth's magnetic field at the Lombok
geomagnetic observatory during 3 (three) years of its initial
operation. This paper specifically presents the results of
declination and inclination measurements. The slowly changes in
the values of declination and inclination are observed clearly,
that the declination values changed by 0.0104°/yr (eastwards),
while the inclination changed by 0.0467°/yr (downward).
Compared to the IGRF-12 model, it shows unusual changes,
which for this region declination should change by 0.0767°/yr
(westward) and inclination by 0.1267°/yr (downward). The
results of the observation provide clues that we have to pay more
attention and scrutiny to the geomagnetic evolution over Nusa
Tenggara region. Further continuous observations on the island
of Lombok are necessary to confirm the tendency of declination
and inclination changes, which will be most useful for integration
with global observations (to know the evolution of the Earth's
magnetic field, especially related to magnetic pole reversal), as
well as with regional observations (to know the fluctuations of the
Earth's magnetic field, especially related to earthquake
precursors).
Full Paper is published on IEEEXplore:
https://ieeexplore.ieee.org/document/8572475
Keywords—Geomagnetic; Observatory;Declination;Inclination;
Lombok; Earthquake
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