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In order to detect
the rising lava,
observations by using
various kinds of
detectors have been made
after the first eruption.
Just before the lava
extrusion, the following results
were obtained.
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Precursory phenomena of extrusion of lava (Part 2) |
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Top of Part 3
Previous p.
Next page
|
In order to detect
the rising lava,
observations by using
various kinds of
detectors have been made
after the first eruption.
Just before the lava
extrusion, the following results
were obtained.
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(1) | Inflation of the volcanic edifice detected by the electromagnetic distance measurement (EDM) |
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In 10 days before the lava extrusion, the southern mountainside swelled at a speed of about 10cm/day. |
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(2) | Inflation of the volcanic edifice detected by tiltmeters |
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In 5 - 8 days before the lava extrusion, the variation of tilt were accelerated. |
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(3) | Thermal demagnetization detected by proton magnetometer |
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In 6 days before the lava extrusion, the magnetism of the rock just under the crater has sharply been weakened. |
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As seen in
the following figure,
these three kinds
of data steeply varied
before and after
the lava extrusion.
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