On the 1st of September 1923 Japan suffered its worst ever natural disaster when an earthquake followed by a tidal wave and fire struck Tokyo. The effects were devastating, 99,331 people were killed and 103,733 people were injured. After this event took place every Japanese citizen was issued with a box of essentials in case another earthquake should strike. In addition to this, they were all given a small amount of training and, in more recent times, 500 researchers have been working to predict if and when this could happen again.
Despite this, in 1995, an event took place that shocked observers worldwide.
The South-central region of Japan is the second-most populated and industrialized area, after Tokyo, with a total population of about 10 million. Kobe on its own has a population of about 1.5 million and is very economically developed. Kobe is one of the richest cities in the world, producing as much wealth on its own as Canada! The Japanese built their houses traditionally out of wood here as wood was flexible and could bend with the ground if an earthquake took place. In modern times heavy tile roofs were put on top of their houses to sustain the strong winds which blew against them.
THE KOBE EARTHQUAKE
On the 17th of January 1995, at 5:46am local time, in the South-central region of Japan, Kobe was just beginning another new day. Suddenly a shock occurred which lasted for just 20 seconds; nevertheless, the damage was phenomenal. The earthquake occurred at a shallow depth on a fault running from Awaji Island through the city of Kobe and was just 20km below the surface.
The earthquake (the first in Kobe in 400 years) killed about 5,000 people and about 35,000 people were injured. Nearly 180,000 buildings were badly damaged or destroyed, and consequently around 350,000 people were made homeless on the night of the earthquake. The life loss caused by the earthquake was the worst in Japan since the 1923 Great Kanto (Tokyo) Earthquake. The economic loss from the 1995 earthquake may be the largest ever caused by a natural disaster in modern times.
The ground moved 7 inches in horizontal shaking in this earthquake, and 4 inches in the vertical direction, the greatest ever recorded in Japan.
The result in movement was: horizontally, 5 feet 7 inches (170 cm), with a vertical slip of 4 feet 3 inches (130 cm).
The maximum displacement point is shown in the photo left.
The cost of repairing the city was roughly ï¿½100,000,000,000 (this does not include indirect economic effects from loss of life, business interruption, and loss of production). Its magnitude was 7.2 on the Richter scale.
Most of the deaths were not caused by the earthquake itself, but by fires which easily set alight wooden houses (150 fires raged for days after the earthquake).
CAUSES OF THE KOBE EARTHQUAKE
Seismologists believe that the Kobe earthquake resulted in an increased amount of damage due to the meeting of hard ground (represented by the Rokko Mountain) and soft ground (the reclaimed land of Port Island). This was similar to the 1989 San Francisco earthquake.
The point at which the Kobe Earthquake took place was at a subduction zone.
Here stress built up in the rocks of the Pacific and Philippine Plates. When this stress was released from these rocks at the plate boundaries by moving, shockwaves travelled through the crust.
THE ENDO FAMILY
The oldest part of the city of Kobe is called Nishinomiya, Mr and Mrs Endo lived here leading a perfectly normal, uneventful life until the day the earthquake struck. Because the Endo’s house was old, it was therefore made of wood and like all the other houses in the area; a heavy tile roof had been built on top of it. On the 16th of January 1995, Mr Endo left his house late in the evening to visit his son and stay the night there. Kazuo Endo (their son) lived in the centre of Kobe in a new apartment block and was happy for his father to stay the night with him.
When the earthquake struck the next day Mrs Endo was tragically killed because the heavy tile roof collapsed, flattening her and the house as it was only made of wood. Mr Endo and Kazuo Endo lived to tell the tale because the new apartment block was made from concrete and had no weak structure points which might have caused it to collapse.
COMPARISONS WITH OTHER EARTHQUAKES
The Maharashtra Earthquake took place on the 1st of September 1993. The ground shook for 30 seconds. This earthquake was unexpected (just as the Kobe Earthquake was) but it was even less likely to happen because it wasn’t on the edge of a plate. Maharashtra is a town in India, which is unfortunately a less economically developed country. Many people lived there because it is a good area for agriculture. Therefore when the earthquake struck no one knew what to do and it took 36 hours for the rescue services to arrive. Even though this earthquake was less powerful compared to the Kobe Earthquake (6.2 on the Richter Scale), more people died because there was no equipment to help find trapped people beneath the rubble.
The San Francisco Earthquake took place in 1989. The citizens there were well prepared for it and as earthquakes were renowned for taking place there, their buildings were made out of a hard, yet flexible material. America is an extremely economically developed country and therefore had good equipment for detecting anyone lost in the rubble and her medication was very advanced. The San Francisco Earthquake happened to take place on the same tectonic plate as the Kobe Earthquake. Luckily only 62 people were killed, even though hundreds were trapped below rubble. The only major problem which occurred was that some rescue services couldn’t reach San Francisco because the Nimitz Bridge collapsed and the Bay Bridge cracked in its centre.