Three history lessons to help reduce damage from earthquakes

Earthquakes don’t kill people,’ the saying goes. ‘Buildings do.’
There is truth in the adage: the majority of deaths during and just after earthquakes are due to the collapse of buildings. But the violence of great catastrophes is not confined to collapsed walls and falling roofs. Earthquakes also have broader effects on people, and the environments we live in.

The United Nations Economic and Social Commission for Asia and the Pacific (ESCAP)’s second Disaster Resilience Week starts in Bangkok on 26 August 2019. Practitioners and researchers have achieved great progress in reducing disaster risk over the past few decades, but we must do more to save lives and protect livelihoods.

Can history help?

Building against disaster

Buildings are a good, practical place to start.

Material cultures offer paths to resilience. A major example is traditional building styles that reduce the threat from seismic shaking. A building is not only a compilation of bricks and stones, but a social element that reflects the cultural life of a community. This is the powerful point made by the Kathmandu-based NGO, National Society for Earthquake Technology (NSET), in a recent report on traditional Nepalese building styles.

NSET, and others working in the field, have identified features of traditional building styles that limit damage during shaking. For example, diagonal struts distribute the load of a roof and limit damage during earthquake shaking.

Historic building with diagonal struts at Patan Durbar Square, Kathmandu, Nepal. Photo: Daniel Haines, 2017

This is important because parts of falling buildings often kill people.

Nearby, in the Himalayan kingdom of Bhutan, the royal government is investigating the earthquake-resistant features of traditional rammed-earth buildings.

An old (c. 400 years?) rammed-earth residential building near Paro, Bhutan. Photo: Daniel Haines, 2017

In fact, seismically-appropriate building styles have evolved along similar lines across a huge Eurasian arc of tectonic unrest, from Italy to Kashmir.

But in most countries, population pressure and the use of cheap, unreinforced concrete construction in growing towns and cities has crowded out traditional construction methods.

Reducing disaster risk always means weighing costs in the present against potential protection in the future. Recovering or encouraging traditional methods is potentially cheaper than enforcing modern seismic engineering.

Long-term health impacts

Focusing only on buildings, though, neglects other important aspects of large earthquakes. These shocks do not only shake buildings down, but can dramatically re-shape landscapes by causing huge landslides, changing the level of water in rivers and leading to flooding.

History shows that these changes can hurt people for months or years after the rubble of buildings have been cleared and reconstruction has begun.

For example, a giant (8.4 Mw) earthquake struck northeast India in 1897. Its epicentre was near Shillong, in the borderlands between British India and China. Luckily, the quake happened in the afternoon, so most people were out of doors. The official death toll – the number of deaths that the colonial government attributed directly to the earthquake – was around 1,500.

Yet officials also thought the poor health conditions that followed the earthquake and the substantial floods that it caused were largely responsible for a major cholera epidemic which killed 33,000 people in the Brahmaputra Valley during the same year. That is twice as many as the previous year.

From the available evidence, it is not yet clear how directly the earthquake and the cholera deaths were linked, but other examples saw similar scenarios. In 1934, another major (8.0 Mw) quake devastated parts of Nepal and North India.

This time, the official death toll in India was around 7,500, but again many more people died from related health complications over the following years. In one district in northern Bihar province, an average of 55,000 people died of fever every year over the next decade. In other areas, malaria was unusually prevalent over the same period.

Government reports held secondary effects of the earthquake responsible for the high death rate.
Events that happened long ago therefore demonstrate the complexity of earthquakes’ impacts, even on the relatively straightforward question mortality. Studying them highlights the need to focus present-day disaster responses on long-term health implications.

Of course, this says nothing of earthquakes’ less concrete, but very important, impacts on social structures, community life, governance or the economy.

History in action

In some cases, historical researchers are contributing directly to initiatives to reduce risk from natural disasters.

Hurricane Katrina showed in 2005 that low-lying New Orleans is terribly vulnerable to storm surge and flooding. Craig Colten, a historical geographer at Louisiana State University, is working with a team of scientists to find solutions by raising the height of the ground in parts of the city while adding forested wetlands on its north shore. Colten is studying analogous historical efforts in other American cities – flood-control measures in nineteenth-century Chicago and responses to hurricanes in Galveston, Texas, around 1900 – as well as examining previous proposals for creating buffers between New Orleans and the sea.

These historical examples provide evidence of what works and what does not. They also highlight the politics of decision-making that help determine whether local communities will support landscape engineering projects.

The international frameworks governing disaster risk reduction such as the Sendai Framework for Disaster Risk Reduction and the Sustainable Development Goals understandably focus on the present, not the past. Historians need to join the conversation to show practitioners that lessons from the past can help build resilience in the future.

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This blog is written by Cabot Institute member Dr Daniel Haines, an environmental historian at the University of Bristol.

Dr Daniel Haines

 

 

Successful trip to Japan: workshop on probabilistic hazard assessment

 

DPRI Kyoto and Cabot Institute

Over the last two days a group from the Cabot Institute has been holding a workshop with colleagues from Kyoto University’s Disaster Prevention Research Institute (or DPRI) on the topic of probabilistic hazard analysis.  On the face of it Japan and the UK are very similar: highly urbanised and complex island societies with high population densities and therefore the potential for serious disruption if natural hazards occur.  Mind you, the earthquake, tsunami and volcano hazards do put Japan in a different league when it comes to potential impacts.  In both countries, robust hazard analysis, planning and decision making is therefore essential to protecting society.  Both countries have a lot to learn from each other, and our recent paper on lessons for the UK from the Fukushima disaster is a case in point.

Cabot members Wendy LarnerColin TaylorSusanna JenkinsJeremy PhillipsKatsu GodaPhilippa Bayleyand myself (Paul Bates) spent two days working with around 30 Japanese colleagues, with Skype presentations from the UK delivered by WillyAspinallJonty Rougier and Tamsin Edwards.  A full programme of the meeting is on our website, and includes pdfs of the presentations for download.  We learned a huge amount about hazard research in Japan and have hopefully begun a large number of research collaborations that will be important for Bristol University for many years.  Our profound thanks go to our Japanese hosts Prof. Eiichi Nakahita and Prof. Hirokazu Tatano, and to the Director of DPRI, Prof. Nakashima.  The photos here give a flavour of the wonderful time we had.

Possibly the most important theme to emerge from the workshop was that whilst probabilistic analysis of hazards (where we give the chance of an event occurring rather than a definite yes/no prediction) is now commonplace in science, there is still a major issue in educating decision makers, governments and the public in how to use such forecasts to take decisions.  Indeed the Daily Mail in the UK has recently been giving the Met Office a hard time for wanting (very sensibly) to move to a probabilistic forecast of rainfall. This shouldn’t be such a big problem, but the fact that it is tells us an awful lot.  Intrinsically people deal with probability information all the time: betting and insurance, for example, are both examples of probabilistic contracts that are well understood by the public. So why do we resist being told about other risks in a similar way.  My gut feeling is that it is to do with the question of responsibility. A probabilistic forecast of risk forces the decision maker (be they Ministers, civil servants or the public) to deal with uncertainty in predictions, whilst insistence on a deterministic forecast puts the responsibility for this onto the scientists who can then be blamed if things go wrong.