Gary Bowering

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Learning Kobe's Lessons

Copyright Gary Bowering 1996. All rights reserved. Story originally published by many papers nationwide during January 1996.

It will soon be a year ago that the Great Hanshin earthquake struck the bustling industrial city of Kobe. In that time, many important lessons have been learned. Gary Bowering finds that New Zealand shares much with Japan, and that we are heeding the lessons taught by the earthquake.

It had just gone a quarter to six that cold morning on 17 January 1995 when the earthquake hit. At 7.2 on the Richter scale of magnitude and lasting just 20 seconds it wasn't the "Big One", and not even as big as the 1931 Hawke's Bay earthquake. Even so, when it was over 5,452 people had lost their lives while more than 33,000 lay injured among the 74,000 damaged buildings.

Among the devastation, fires raged uncontrolled in the crowded urban areas because water mains were broken and roads impassable to fire fighters and other rescue services.

The Hanshin district -- after the Tokyo-Yokohama area, the country's second most important industrial region -- lay in ruins with damage estimated to cost around NZ$200 billion.

At first glance, New Zealand has little in common with Japan. But quick glances can be deceptive.

"Under the veneer of different language, population and culture, there are many close parallels between New Zealand and Japan," says Professor Bob Park who led a team of members of the New Zealand National Society for Earthquake Engineering (NZNSEE) to Kobe after the quake. "Both countries are a long series of narrow islands with a mountainous backbone; both are relatively small (about 370,000 square kilometres for Japan; 270,000 for New Zealand); most of the population of both is settled close to the coast, often on alluvial plains with soft soils; and both are on the Pacific's 'Ring of Fire'.

"This last point is very important, for it means that both nations are on one of the huge blocks of the Earth's crust -- called tectonic plates -- that are moving past each other. As the plates rub against, sink under or rise over one another, they generate enormous amounts of energy, releasing it as heat (causing volcanic activity) or in sudden movements, causing earthquakes. New Zealand and Japan share this propensity for disaster.

"Kobe and Wellington have some even closer similarities. Both cities are ports, both have built-up areas on alluvial ground at the base of steep hills, both have transport and other service networks (called lifelines) made vulnerable by the terrain, and the Wellington fault is expected to produce earthquakes of similar nature to the Kobe one, although perhaps a little stronger and twice as often."

After such a natural disaster, each nation can learn from the other, and that was the rationale behind the visit by the members of the New Zealand National Society for Earthquake Engineering, and of other teams since. Every piece of knowledge helps, because, as Bob Park points out, New Zealand scientists and engineers are not over-confident about either the likely size of earthquake disasters in New Zealand, or their effects.

Even so, the Society's comprehensive report, published earlier this year, highlights some thought-provoking lessons learnt by the Japanese -- and finds that these are equally applicable in this country. It also highlights that, rather than shrugging our shoulders and saying there's nothing that can do to mitigate damage and aid recovery, there is a great deal we can be done before disaster strikes. Indeed, recent mitigation measures that have already been taken in New Zealand are likely to be effective in reducing damage -- and reducing the time it will take to recover from such an earthquake.

Lessons for New Zealand

"The good news is that modern earthquake resistant materials performed well in Japan," says David Middleton, general manager of New Zealand's natural disaster insurers, the Earthquake Commission (EQC). "Water, gas and sewerage lines with seismic joints and made from flexible materials suffered much lower failure rates than older lines."

Many local authorities in this country are actively replacing older pipes with better ones, so most localities should not fare as badly during a disaster. The biggest problem area -- as demonstrated in Kobe -- is where the lines from mains and meters join buildings. NZNSEE's Bob Park says that these are still prone to failure.

"Ground damage, caused by liquefaction of the soil and subsequent settling or movement, caused much of the destruction of underground services. Although many buildings survived in areas of ground damage, the services to them did not. Why? Most buildings -- especially those of more than one storey -- are on piles which are deep enough to reach below the top layer subject to liquefaction. When the top layer shifts or settles so do the pipes laid in it. These buildings don't move, but the connections are severed.

"Although buildings may survive with little or no damage, they may be unusable because they have no water or sewerage. These lifelines, as they're called, need to be designed to resist damage. Functioning utility services are vital for rapid recovery with minimum economic loss."

These problems are being researched, however, and New Zealand organisations, like the Wellington Earthquake Lifelines Group, are keenly watching the results. For example, flexible joints for connecting water supply from mains into buildings are now being developed overseas.

Other lifelines (the term covers road, rail, telephone, electricity, gas, sewerage and stormwater) also suffered damage in Kobe. The lesson here for New Zealand is that individuals need to be prepared, and shouldn't wait for engineering achievements to save them. Water, power and other 'vital' services may not be available to many buildings, or even whole areas, for some time after an earthquake.

"Every Kiwi must ask themselves how they will cope without water, sewerage, gas, power and so on, and then must do something to make sure that they can. The guidelines in the back of the phone book are good starting points, and many local authorities and utility companies have good information freely available," says Professor Park.

Fortunately, the experience in Kobe indicates that most utilities can be restored to most areas very quickly after an earthquake, if good preparations are made.

About a quarter of the region's households lost power during the earthquake. Within two hours, switching operations successfully restored power to almost 40% of those homes. After eight hours, almost 50% of lost power had been restored, and full restoration was achieved in just seven days.

"Kansai Electric Power Company had, like other Japanese utilities, adopted the earthquake design standards set in 1980, and most of its facilities performed well," says the Earthquake Commission's David Middleton. "It had also designed a high degree of redundancy and flexibility into its network, using a strongly interconnected grid, and had a diversity of equipment types. It had also stored some essential materials and vehicles -- such as power generation vehicles -- for emergency use.

"Other Japanese power companies provided personnel, equipment and vehicles. The power generation vehicles were used to supply service facilities such as police, fire, hospitals, and community shelters.

"Even though only half of its staff were able to get work on the day of the earthquake, the preparedness, planning and practice that Kansai Electric Power Company made a normal part of its business operation helped ensure a rapid response and effective recovery. Getting the power on quickly was also a great boost to morale."

Other utilities also did well. Gas supply was suspended to many customers soon after the earthquake, and not restored until lines had been checked or repaired. However, some homes remained without gas for nearly three months.

The main water supply lines in Kobe were restored relatively quickly, and more than half of the households without water after the quake had supply back within 11 days. Full restoration took almost two and a half months.

Sewerage and stormwater drainage systems were badly damaged in Kobe, but service was able to be restored quickly, thanks in part to a high availability of resources. Even so, full recovery is likely to take another year, and to rely on extensive funding from Japan's national government.

"Being prepared is the main lesson for New Zealand and, I think, most of our utility companies are doing very well. Our design standards are as stringent as, or even more stringent than, those in Kobe. There is still work to be done in some areas though, such as cooperative arrangements between utilities and other organisations, and in ensuring access to essential supplies, materials and personnel," says David Middleton.

Bob Park agrees.

"Organisations need to be ready to react, and react in the right way, when required. And there needs to be resources (or failsafe ways of securing resources) in place ready for when disaster strikes. Without these, more lives will be lost, reconstruction delayed, and the economy unduly affected."

Frozen arteries

Kobe's transportation system, like its utilities, is similar to that in many parts of New Zealand, with road and rail running together, says Bob Park.

"Even though there were eight parallel east-west routes serving the area, all but one were impassable. In addition almost all of the criss-cross feeder routes were damaged. Transport was brought to a standstill after the quake.

"Most of the damage to the city's transportation routes caused by the Great Hanshin earthquake was due to collapsed elevated spans, and pier failures. Even though many local surface roads remained undamaged or were quickly made operational, others were damaged beyond use or blocked with rubble.

"In addition to severely restricting the movement of rescue and repair operations in the hours following the earthquake, the damage caused chaos for weeks afterwards with long delays for all services -- car, bus and train. What was a 40 minute trip from Osaka to Kobe routinely took three to four hours. The costs to business through lost time, and stress on individuals caused by such hassles, is collectively huge."

As a result of experience garnered from California's 1994 Northridge earthquake and that of Kobe (both, coincidentally, occurring on the 17th of January), part of State Highway 1 -- Wellington's Thorndon overbridge -- is being upgraded. Other areas of New Zealand transportation can also benefit from overseas experience.

"Kobe's port facilities (largely built on reclaimed land) were badly damaged, with the few serviceable wharves being used for relief and emergency supplies. Those companies still able to manufacture have been forced to use alternative -- and more expensive -- transport, as have importers of needed supplies and construction materials. We believe that, over the long-term, the damage to the port is likely to be the single largest source of cost to the Kobe economy."

Professor Park estimates that restoring the port will cost NZ$10 billion. He also notes that, with good planning, port and harbour restoration or extension could assist with city clearance, the rubble from destroyed buildings being used as fill.

The area's two main airports, in contrast, survived unscathed. Both were operational within 24 hours, after checks for damage had been made. Even with airlifts possible, the task of getting the supplies from the airports to where they were needed was formidable.

"Clearly, the lesson here for New Zealand is that people will need to be largely self-reliant. Emergency services will have reduced capability (perhaps themselves suffering damage to buildings and vehicles), restricted mobility because of impassable roads and streets, and a vastly higher than normal workload.

"Even weeks or months after the event, transport systems may be in such a state that items such as food and clothing may be difficult -- and expensive -- to obtain. Individual preparations for disaster will be as important as large-scale plans to deal with rubble clearance, reconstruction, and systems for relieving congestion."

These are lessons that national and local organisations across New Zealand have learnt from this, and other disasters, and have taken to heart. The Earthquake Commission, for example, is developing a comprehensive Catastrophe Response Plan, and around the country members of groups like the Wellington Earthquake Lifelines Group are working through plans of their own.

Get coordinated

"Inter-agency cooperation is important, and plans need to be flexible. This lesson was taught throughout the Kobe disaster. Even simple decisions like where to put the rubble from demolished buildings become complex after a major earthquake. New Zealand has the added legislative complications of consent procedures under the Resource Management Act and some aspects of the Building Act. Many experts say that these will not work in an emergency situation, and may have to be suspended or a moratorium imposed.

"Each agency has its own requirements and methods. New Zealand local and national Government agencies, rescue organisations, utilities suppliers, and reconstruction organisations (such as insurers and materials suppliers) need to work together, and make decisions together, for optimum benefit," says Bob Park.

New Zealand has already taken on board the value of cooperation and coordination. All of the organisations involved in disaster response and recovery -- from Police and Civil Defence, through local authorities and utility companies, to insurers like the Earthquake Commission -- are seeking some inter-agency comment and input on their individual (and often joint) plans. One good step in this direction is the just-released Emergency Services Review.

Perhaps the greatest lessons from Kobe have been learnt from studies of damage to buildings. Every disaster reveals something new -- and tests the performance of new designs and materials, says Bob Park. The overwhelming response has been that modern earthquake resistant structures are much better than older buildings.

"The buildings that fared worst in the shake were traditional Japanese houses. Their two storey wood, bamboo, mud and tile construction did not stand up to the ravages of the earthquake, and these structures were where many of the fires started.

"Western style houses fared very well. The NZNSEE team found no failures among the houses of this type they saw. Many of the homes of this style were constructed relatively recently. These are the type of homes that are most common in New Zealand.

"Commercial and apartment buildings also showed variations according to type. Small traditional Japanese commercial buildings, being narrow, long and three to four stories high, performed poorly, many collapsing and also contributing to the fires."

Western-style commercial buildings generally fared better. Those built after 1981, when Japan introduced a new earthquake design standard, suffered least damage.

"Most of these performed very well -- even the high rise glass-clad towers. In general, damage was caused where structurally separated buildings rocked against each other. They basically banged together.

"Even so, some modern buildings did suffer damage. In some cases this was caused by failure of external high strength structural steel boxes, believed to have been made brittle by the low outside temperature at the time of the earthquake.

"Older low rise commercial buildings -- three to five stories high and with their width and depth similar to or greater than their height -- showed more damage, ranging from cracking near the base through to bottom storey collapse. New Zealand has many of this type.

"A large number of the commercial buildings in Kobe were older medium and high rise -- 10 to 20 storeys high, and constructed similarly to the older low rise buildings (reinforced concrete and, often, relatively heavy concrete cladding). Performance was also similar to the low-rise buildings, although many showed more damage at higher levels and a significant number collapsed around the third to fifth storey.

"Some ended up on a tilt after rocking back and forth in the soft soils. A good proportion of New Zealand commercial buildings are of this older (pre-1981) construction.

"Statistics drive home the extent of the damage. The Ohbayashi Corporation examined 233 buildings. Of post-1981 buildings 6% were classified 'danger -- keep out' and 11% 'caution -- restricted use'. In contrast, 36% of pre-1971 buildings were classified 'danger ­ keep out'."

Similarities...

Bridges, industrial structures and the port were also examined by the team.

"From these detailed inspections, and discussions with Japanese experts, we were able to determine what types of construction resulted in what kinds of failure. From this, we have been able to provide some indication of what might happen to buildings here in the event of a large shake."

The prognosis is not bad, says Professor Park, but we have no reason to be complacent. Many New Zealand buildings are likely to show similar damage to that demonstrated in Kobe's western-style structures.

"For older buildings, investing in retro-fitting for earthquake resistance can be worthwhile. Newer buildings are more likely to perform well, but there will still be some damage. As new materials, designs and components are developed, and as older buildings are replaced or retro-fitted, the amount of damage in any given earthquake will reduce. But it won't be eliminated."

There are other direct lessons to be taken from Kobe's experience, many of them the domain of urban planners, and all things that many authorities in New Zealand are aware of and that many are working through.

Among these: