Japanese tsunami earthquake
The
1896 Sanriku earthquake
(
明治三陸地震
,
Meiji Sanriku Jishin
)
was one of the most destructive seismic events in Japanese history.
[3]
The 8.5
magnitude
earthquake occurred at 19:32 (local time) on June 15, 1896, approximately 166 kilometres (103 mi) off the coast of
Iwate Prefecture
,
Honshu
. It resulted in two
tsunami
waves which destroyed about 9,000 homes and caused at least 22,000 deaths.
[4]
The waves reached a then-record height of 38.2 metres (125 ft); this would remain the highest on record until waves from the
2011 T?hoku earthquake
exceeded that height by more than 2 metres (6 ft 7 in).
[5]
From the tsunami records the estimated
tsunami's magnitude
is (M
t
= 8.2),
[6]
much greater than expected for the seismic magnitude estimated from the observed seismic intensity (
=7.2).
[2]
This earthquake is now regarded as being part of a distinct class of seismic events, the
tsunami earthquake
.
[7]
Geology
[
edit
]
The epicenter lies just to the west of the
Japan Trench
, the surface expression of the west-dipping
subduction
zone. The trench forms part of the
convergent boundary
between the
Pacific
and
Eurasian
plates.
[2]
Magnitude
[
edit
]
The unusual disparity between the magnitude of the earthquake and the subsequent tsunami may be due to a combination of factors:
[2]
- the tsunami was caused by a slope failure triggered by the earthquake
- the rupture velocity was unusually low
Scientists believe the effect of subducted sediment beneath the
accretionary wedge
was responsible for a slow rupture velocity. The effects of a 20° dipping fault along the top of the subducting plate was found to match both the observed seismic response and tsunami, but required a displacement of 10.4 m.
[2]
The displacement was reduced to a more reasonable value after the extra uplift caused by the deformation of sediments in the wedge and a shallower fault dip of 10° was considered. This revised fault model gave a
magnitude
of M
w
=8.0?8.1. A figure much closer to the estimated actual tsunami magnitude.
[8]
A magnitude of 8.5 on the
moment magnitude scale
has also been estimated for this event.
[1]
Tsunami
[
edit
]
On the evening of June 15, 1896, communities along the
Sanriku coast
in northern Japan were celebrating a
Shinto
holiday and the return of soldiers from the
First Sino-Japanese War
. After a small earthquake, there was little concern because it was so weak and many small tremors had also been felt in the previous few months. However, 35 minutes later the first tsunami wave struck the coast, followed by a second a few minutes later.
[3]
[9]
The damage was particularly severe because the tsunamis coincided with high tides. Most deaths occurred in
Iwate
and
Miyagi
although casualties were also recorded from
Aomori
and
Hokkaido
.
The power of the tsunami was great: large numbers of victims were found with broken bodies or missing limbs.
[3]
As was their normal practise each evening, the local fishing fleets were all at sea when the tsunamis struck. In the deepwater, the wave went unnoticed. Only when they returned the next morning did they discover the debris and bodies.
[10]
Wave heights of up to 9 meters (30 ft) were also measured in
Hawaii
. They destroyed wharves and swept several houses away.
[4]
[11]
The word tsunami (from
tsu
"harbor" and
nami
"waves") was coined due to this disaster.
[12]
Legacy
[
edit
]
Preventive coastal measures were not implemented until after another tsunami struck in 1933. Due to higher levels of tsunami awareness, fewer casualties were recorded following the
1933 Sanriku earthquake
.
[3]
Nevertheless, the
earthquake of 11 March 2011
caused a huge tsunami that resulted in thousands of deaths across the same region and the
nuclear disaster at Fukushima
.
See also
[
edit
]
References
[
edit
]
- ^
a
b
Nishimura, T.; Miura S.; Tachibana K.; Hashimoto K.; Sato T.; Hori S.; Murakami E.; Kono T.; Nid K.; Mishina M.; Hirasawa T. & Miyazaki S. (2000). "Distribution of seismic coupling on the subducting plate boundary in northeastern Japan inferred from GPS observations".
Tectonophysics
.
323
(3?4): 217?238.
Bibcode
:
2000Tectp.323..217N
.
doi
:
10.1016/S0040-1951(00)00108-6
.
- ^
a
b
c
d
e
Tanioka, Yuichiro; Sataka K. (1996).
"Fault parameters of the 1896 Sanriku Tsunami Earthquake estimated from Tsunami Numerical Modeling"
.
Geophysical Research Letters
.
23
(3): 1549?1552.
Bibcode
:
1996GeoRL..23.1549T
.
doi
:
10.1029/96GL01479
.
hdl
:
2027.42/95213
. Archived from
the original
on 2011-05-31
. Retrieved
2009-10-19
.
- ^
a
b
c
d
e
Nakao, Masayuki.
"The Great Meiji Sanriku Tsunami June 15, 1896, at the Sanriku coast of the Tohoku region"
. Archived from
the original
on 2008-12-23
. Retrieved
2009-10-18
.
- ^
a
b
USGS.
"Today in Earthquake History: June 15"
. Retrieved
2009-10-18
.
- ^
"March 11th tsunami a record 40.5 metres high NHK"
. .nhk.or.jp. 13 August 2011. Archived from
the original
on 28 July 2011
. Retrieved
15 June
2018
.
- ^
Abe, K. (1981). "Physical size of tsunamigenic earthquakes of the northwestern Pacific".
Phys. Earth Planet. Inter
.
27
(3): 194?205.
Bibcode
:
1981PEPI...27..194A
.
doi
:
10.1016/0031-9201(81)90016-9
.
- ^
Kanamori, H. (1972).
"Mechanism of tsunami earthquakes"
(PDF)
.
Phys. Earth Planet. Inter
.
6
(5): 346?359.
Bibcode
:
1972PEPI....6..346K
.
doi
:
10.1016/0031-9201(72)90058-1
. Archived from
the original
(PDF)
on 2011-06-14.
- ^
Tanioka, Y.; Seno T. (2001).
"Sediment effect on tsunami generation of the 1896 Sanriku tsunami earthquake"
(PDF)
.
Geophysical Research Letters
.
28
(17): 3389?3392.
Bibcode
:
2001GeoRL..28.3389T
.
doi
:
10.1029/2001GL013149
.
S2CID
56014660
. Archived from
the original
(PDF)
on 2011-06-10
. Retrieved
2009-10-19
.
- ^
Corkill, Edan, "
Heights of survival
",
Japan Times
, 12 June 2011, pp. 9?10.
- ^
Kusky, Timothy M. (2003).
Geological hazards: a sourcebook
. Greenwood Press. p. 312.
ISBN
978-1-57356-469-4
.
- ^
Hatori, Tokutaro (1963).
"On the Tsunamis along the Island of Hawaii"
(PDF)
.
Bulletin of the Earthquake Research Institute
.
41
: 49?59. Archived from
the original
(PDF)
on 2011-10-06.
- ^
Harper, Douglas.
"tsunami (n.)"
.
The Online Etymology Dictionary
. Retrieved
4 March
2023
.
Japan Trench megathrust earthquakes
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Notable Japan Trench megathrust quakes
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Plate tectonics
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Historical
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20th century
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21st century
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Related articles
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Earthquakes in 1890s
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1891
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1892
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1893
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1894
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1895
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1896
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1897
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1898
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1899
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†
indicates earthquake resulting in at least 30 deaths
‡
indicates the deadliest earthquake of the year
|