MARCH 11, 2011, Japan Tsunami – Honshu

• Earthquake Magnitude : 9.0
• Coordinates : 38,322°N 142,369°E
• Depth : 32 km
• Distance :129 km east of Sendai

An earthquake with a magnitude of 9.0 occurred at 05:46 Greenwich Mean Time (14:46 local time) on March 11, 2011, 130 km from the coast, off the coast of Tohoku District in the North East of Japan. The earthquake center is at 38.322°N, 142.369°E coordinates and the focal depth is 24 kilometers. The earthquake, named Taiheiyou by the Japan Meteorological Agency, caused damage in the northeastern cities of Japan and was felt strongly in the capital Tokyo, 350 km south of the earthquake center. After the earthquake, tsunami waves with an amplitude higher than 15 meters and a period of approximately 1 hour in the deep sea reached the nearest shore in approximately 25 minutes.

The largest known tsunami in the region throughout history is the “Jogan tsunami” that occurred in 869. The information obtained shows that the tsunami at that time reached the Tagajo castle, which is 4 km away from the coast, and caused about 1000 casualties. However, it was observed that the earthquake and tsunami experienced were much larger than the Jogan earthquake and tsunami.

It has been observed that when the waves reach the shores, they pass through the coastal walls and progress for 4-5 km in the coastal areas, while the ocean waters entering from the river mouths reach up to 10 km from the shore along the river. Waves swept through many places along the north east coast of Japan, destroying infrastructure and buildings. Since the general structure of the region is a single or two-storey light wooden structure, the effect of strong currents and waves advancing on land has been completely destructive. However, it has been observed that the damage in concrete structures is much less than in wooden structures.

In addition to these painful losses, overheating could not be prevented due to the failure of forced cooling as a result of the damage to the cooling system at the Fukushima Nuclear Power Plant and the failure of the backup systems. As a result, nuclear disaster due to radioactive leakage caused by human influence was added to the series of natural disasters that started with an earthquake and continued with a tsunami.