JAPAN - EARTHQUAKE AND TSUNAMI OF 3 MARCH 1933 IN SANRIKU
George Pararas-Carayannis
INTRODUCTION
A great earthquake occurred on March 2, 1933 (UTC DATE) in the Sanriku region of Japan and generated a destructive tsunami that caused extensive damage along the Sanriku coast of the Tohoku region of the island of Honshu.
THE EARTHQUAKE
Date and Origin Time - March 3, 1933 at 02:31 AM (Japan Standard Time); March 02 at 17:31 UTC
Magnitude - Mw 8.4
Epicenter - At 39.14N 144.31?E, off northeast Honshu along the coast of Sanriku and at about 290 klms (180 mi) east of the city of Kamaishi, Iwate. This is approximately the same area where the great 1896 Meiji-Sanriku earthquake generated a very destructive tsunami.
Focal depth - Shallow ( less than 35 km / 21.7 miles).
Aftershocks - A large vigorous aftershock sequence followed the main earthquake. About three hours after the main quake there was strong afteshock with a magnitude of 6.8. Over a period of six months there were 76 more aftershocks with magnitudes of 5.0 or greater. The significance of the aftershock distribution as it relates to tsunami generation, is discussed in a subsequent section.
Death Toll and Damages - The earthquake did little damage to buildings. Most of the damage was caused by the tsunami. More than 3,000 people lost their lives.
THE TSUNAMI
The tsunami was recorded throughout the Pacific region.
Near-field Effects
Thirty to sixty minutes following the earthquake, tsunami waves begun to strike the Sanriku coastal region as well as the southern coasts of Hokkaido. Most of the damage in the Sanriku region was caused by the tsunami. More than 7,000 homes were extensively damaged and 4,885 were washed away. Tsunami waves reached a height of 28.7 metres (94 ft) at Ryori Bay, Honshu, causing numerous deaths and extensive destruction to homes and structures. At the town of Taro - which is part of Miyako City in Iwate - the waves reached a height of 10.1 meters destroying 98% of the houses and killing about 42% of its people (763).
At Yoshihama which is close to Ryori Bay, another 982 people died. At Ofunato the runup heights ranged from 2.0 to 2.5 meters and the damage to houses was not as great as at Akazaki where the waves ranged from 3.0 to 3.5 meters and destroyed 50 homes.
A total of 3,064 were killed and 1,092 were injured from this event.
Far-field Tsunami Effects
Hawaiian Islands (source: G. Pararas-Carayannis, 1969)
Midway Island - Notable tsunami waves ranging in height from 4.5 to 6.5 meters reached Midway Island between 11:05 and 13:00 (local time).
Oahu - The first wave reached Honolulu 7.6 hours after the earthquake in Japan but the waves were small and caused no damage.
Maui - Three small waves arrived in Lahaina Harbor on the island of Maui. The first arrived at about 05:00 and the water receded 10-14 meters horizontally. The second wave arrived at 05:30 and the last wave a few minutes later.
Hawaii Island - At Hilo the first wave arrived 8.6 hours after the earthquake at 15:36. Maximum amplitude at the tide gauge was only 0.5 meters and no damage was reported.
At Kawaihae the tsunami travel arrived at 15:30 and some damage was reported. At Kailua-Kona a series of ten large waves were observed starting at 15:20. The last was reported to be the largest.
At Napoopoo the water receded to 2.4 meters below mean sea level, rose to 2.9 meters (9.5 ft)and the total vertical range (double amplitude) was 5.3 meters. The seventh wave was the highest. Ther was some damage. Walls were washed down, boats were unmoored and capsized, houses were flooded and moved, objects were washed out to sea, interior furniture in houses was damaged. There was also some damage in Kaaluu.
Historic Tsunamis along the East Coast of Japan
The Sanriku coast of Japan is characterized by significant seismic activity. Large earthquakes have generated destructive tsunamis in the past. The following two were very destructive in the Sanriku region.
1896 August 31 - At 8:06AM on August 31st a great earthquake (named as the Meiji Sanriku earthquake of 1896) occurred off the Sanriku coast. Its epicenter was at 39.5N, 140.6E. Its magnitude estimated to have been about 8.4. About 22,000 people were killed - mostly by the tsunami.
1960 May 24 - The 1960 tsunami generated by the earthquake in Chile impacted the entrire Japanese/Pacific coastline with waves ranging in height up to 5 meters. The tsunami was particularly destructive at Ofunato, on the southern Sanriku coast. At Ofunato and Akazaki the tsunami destroyed or washed away 432 houses and killed 52 people (Hatori et al., 1982)
REFERENCES
Hatori T., Aida I, Koyama M and T. Hibiya, 1982. Field Survey of the Tsunamis In Inundating Ofunato City - The 1960 Chile and 1933 Sanriku Tsunamis. Bull. of the Earthquake Research Institute, Vol. 57, pp. 133-150.
Iida, K., D.C. Cox, and Pararas--Carayannis,
George. Preliminary
Catalog of Tsunamis Occurring in the Pacific Ocean. Data
Report No. 5. Honolulu: Hawaii
Inst.Geophys.Aug. 1967.
Pararas--Carayannis,
G., Catalog
of Tsunamis in the Hawaiian Islands. Data Report Hawaii Inst.Geophys.
University of Hawaii. Jan.
1968
Pararas--Carayannis,
G., Catalog
of Tsunami in the Hawaiian Islands. World Data Center
A- Tsunami
U.S.
Dept. of Commerce
Environmental Science Service Administration
Coast and Geodetic Survey, May 1969.
Pararas--Carayannis,
G and
Calebaugh P.J., Catalog of
Tsunamis in
Hawaii, Revised
and Updated
, World
Data Center
A for
Solid Earth
Geophysics, NOAA,
78 p.,
March 1977.
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©1982 - 2010 Dr. George Pararas-Carayannis - All rights reserved
Last update: MAR, 2010 |
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