Tag Archives: Feature

Corruption and earthquake hazards

Earthquakes are caused by the sudden release of energy stored on fractures in the Earth’s crust called faults. Every year they are responsible for thousands of fatalities around the world.

For this post I’d like to focus on the role of corruption in the building industry and its impact on lives lost in earthquakes. The global construction industry was worth $8.7 trillion in 2012[3] and is recognised as being the most corrupt segment of the global economy[1].

Corruption in this industry takes the form of using inadequate and/or insufficient building materials, bribes to inspectors and civil authorities, substandard assembly methods and the inappropriate siting of buildings. Spontaneous building collapses even without earthquakes, such as the 2013 Savar factory collapse in Bangladesh, which killed 1129 people, are a stark reminder of the consequences of construction oversight and a terrifying view into what could happen if there is an earthquake in these regions.

Dhaka_Savar_Building_Collapse_W.Commons-rijans_edited
The Savar building collapse near Dhaka Bangladesh, which killed 1129 garment factory workers. Source: Wikimedia Commons

The 1999 Izmit earthquake (magnitude 7.4) in Turkey resulted in around 18,00 deaths. After the earthquake, inspectors found that nearly half of all the structures within the damage zone had failed to comply with building regulations[1].

Nicholas Ambraseys and Roger Bilham calculated that almost 83% of all deaths from building collapse in earthquakes in the last 3 decades occurred in countries that are poor and anomalously corrupt[4].

Corruption by itself is dangerous but when combined with poverty, it is disastrous. Corruption, poverty and ignorance essentially become indistinguishable for many low income countries. And even if corrupt practices are eliminated these countries will have inherited a building stock that is of poor quality and prone to failure in the next earthquake.

corruption_kills_v2
A pertinent quote from the famous Charles Richter in his 1970 retirement speech.

However, it’s not all bad news. There are some great examples of how reconstruction can happen under correct management and regulations to improve resilience to earthquakes and other natural hazards. For example, in 2012 the Turkish government passed the Law on the Regeneration of Areas Under Disaster Risk. Under these new guidelines all buildings that are not up to current earthquake risk standards will be demolished and rebuilt.

The reconstruction of the Macedonian capital of Skopje after it was destroyed in an earthquake in 1963 is another great example. Not only was all the infrastructure rebuilt to be earthquake-resistant, the city planners also ensured that the river Vardar was re-routed in order to control future flooding[5].

Achievements on this scale requires strong governance and management, and transparent national and local administration. With the rapid growth of cities into so-called megacities (>10 million population), often in high earthquake risk regions, this is even more important. We have yet to have an earthquake that has killed a million people. But at the rate these cities are growing under limited to no management, such an event might not be too far in the future.

More Information:
[1] Global Corruption Report 2005: Corruption in construction and post-conflict reconstruction, Transparency International
[2] Global Construction 2020: A Global Forecast for the construction industry over the next decade to 2020. (2010)
[3] Global Construction 2025:  A Global Forecast for the construction industry to 2025. (2013)
[4] Ambraseys, N. & Bilham, R., 2011
[5] Vladimir B. Ladinski 2010

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Earthquake risk in the Himalaya

By Victoria Stevens

Earthquakes have not been releasing energy as fast as the energy has been building up along the Himalayan arc. Meaning that there could be a giant earthquake in the region placing millions at risk.

A new study of the 2000 km long Main Himalaya Thrust, the largest earthquake generating fault in the Himalaya, has revealed that large quakes could occur in any location along the Himalayan arc.

Unlike in subduction zones, where some patches of the fault are moving, or ‘creeping’ at a constant speed, in the Himalaya we don’t see any creeping patches. This means that the fault is fully ‘locked’, i.e. strain energy is building up most of the time. This energy is released suddenly during earthquakes. Because there are no creeping patches, there are no barriers to rupture, which means once an earthquake has started, it could rupture a very long way along the fault without anything to limit its size.

The degree of 'locking' on the Main Himalayan Thrust. Where the fault is red, its fully locked and white where its not locked. Source: Stevens and Avouac 2015
The degree of ‘locking’ on the Main Himalayan Thrust. Where the fault is red, its fully locked and white where its not locked. Source: Stevens and Avouac 2015

The study shows that the pattern of coupling, i.e. the degree of fault locking, has been stationary with time. From the coupling pattern, the rate of moment build-up can be found. This is how much energy is building up each year, and is also the amount that needs to be released in earthquakes if all the energy is released seismically.

Earthquakes have not been releasing energy as fast as the energy has been building up, so we may expect very large earthquakes in this region in the future. Studies of ancient earthquakes have shown that quakes approaching magnitude 9 have occurred previously in both the western and eastern halves of the Himalayas. It is not impossible that these giant earthquakes could occur again.

night_lights
Night lights show large population densities living in the shadows of the Himalaya.

This has important implications for seismic hazard in the region. The population living in the Himalayas has increased dramatically in the past few decades, and most buildings are not resistant to large shaking caused by earthquakes. As we saw with the recent devastating April Gorkha-Nepal earthquake, the Himalayan countries prone to earthquakes are not yet prepared to meet all the challenges this natural hazards present.

Read the full journal article titled: Interseismic coupling on the main Himalayan thrust

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Victoria Stevens is a PhD graduate student at the California Institute of Technology (Caltech).

“So long, and thanks for all the fish” … the end of coral reefs?

Leading scientist says that even ambitious greenhouse gas reduction targets will not be able to save the world’s coral reefs.

Professor Peter Sale from the University of Windsor, Canada claims that coral reefs, as they were 50 years ago, cannot be saved from climate change – even if the climate change talks in December this year (COP21) are “wildly successful”.

Professor Sale unveiled the depressing results today at the Goldschmidt conference, a gathering of the world’s top geochemists in Prague.

He said, “Even if Paris is wildly successful, and a treaty is struck, ocean warming and ocean acidification are going to continue beyond the end of this century. This is now serious; I find it very unlikely that coral reefs, as I knew them in the mid-1960s, will still be found anywhere on this planet by mid-century. Instead, we will have algal-dominated, rubble-strewn, slowly eroding limestone benches.”

A bleached coral. These events will become more common with global warming.
A bleached coral. These events will become more common with global warming.

Globally coral reefs are generally found in tropical waters. Not only are they some of the world’s most productive ecosystems they also deliver ecosystem services in tourism, fisheries and coastline protection. The global economic value of coral reefs has been estimated to be US $375 billion per year!

Loss of reefs will be a fatal blow for the animals and communities who rely on them

While the global policy debate has been about trying to limit global warming to 2 degrees by the end of the century, Professor Sale claims that this won’t be enough to save coral reefs.

“I see little hope for reefs unless we embark on a more aggressive emissions reduction plan. Aiming for CO2 at 350ppm, or a total warming of around 1°C is scientifically defendable, and would give reefs a good chance; a number of coral reef scientists have called for this.”

Sale summarised:

“Knowing what we are doing, do we have the ethical right to eliminate an entire ecosystem from this planet? It’s never been done before. But watching as our actions lead to the loss of all coral reefs on the planet is like removing all rainforests. I don’t believe we have that right”.

Double warning time for volcanic lahars

By Robert Jones

Real-time rainfall data can be used to potentially double warning times for rain-triggered lahars on the slopes of Tungurahua Volcano, compared existing ground-based detection methods.

Tungurahua volcano is located in the Eastern Cordillera of the Ecuadorian Andes and its current period of eruptive activity has been ongoing since 1999. This intermittent activity has resulted in the deposition of a lot of loose unconsolidated pyroclastic gravel, dust and ash on the slopes of the volcano.

A recent Tungurahua at night. Source: Dr. Carlos Costales Terán, Wikimedia Commons
A recent Tungurahua eruption at night.
Source: Dr. Carlos Costales Terán, Wikimedia Commons

During heavy rainfall, for which this region is renown, this loose material gets mixed into the rain water flowing off the volcano and results in extremely dangerous rain-triggered lahars, or volcanic mudflows. Think flash floods and giant rivers of mud and rock rolled into one.

The city of Baños lies approximately 8 km north of the summit of the volcano and is a very popular tourist destination, with its population increasing from approximately 18,000 to around 50,000 during holiday periods. The primary road linking Baños with the Pan-American Highway and other provincial cities crosses several lahar-prone drainages of Tungurahua and these flows pose a significant risk to infrastructure within these valleys.

Rain-triggered lahars have not caused any fatalities at Tungurahua but cars have been buried, road crossings inundated and the El Salado Baths (a popular visitor attraction) have nearly been inundated by flows in previous years.

An incoming lahar from mount Tungurahua. Source: IGEPN
An incoming lahar from mount Tungurahua.
Source: IGEPN

The volcano is monitored from the Tungurahua Volcano Observatory (OVT), operated by the Instituto Geofisico, Escuela Politécnica Nacional (IGEPN). The primary methods of lahar monitoring are detection by Acoustic Flow Monitors (AFMs), which measure ground vibration as the flow passes and also flow identification by a community-based monitoring system consisting of a network of volunteers known as Vigias.

Analysis of both the rainfall and lahar record between March 2012 and June 2013 indicated that peak rainfall intensity can be a key indicator of a potential lahar occurrence. The peak rainfall intensity during a particularly rainy period is used along with previous knowledge of the amount of moisture already in the landscape to estimate the probability that a lahar will exceed a pre-defined flow size. This method was tested using the July-December 2013 lahar and rainfall records and not only did our probabilities effectively predict the occurrence of lahars, but peak estimated lahar probability was consistently reached prior to lahar detection by the Acoustic Flow Monitor network. This probabilistic analysis produced an average of 24 additional minutes of warning time during the test-period.

Read the full paper at: http://link.springer.com/article/10.1007%2Fs00445-015-0946-7

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Robert Jones is a PhD research student in the School of Earth and Environment at the University of Leeds.

Here’s an example from Ubinas volcano in neighbouring Peru, of the force and destructive power of lahars.

The Silk Road helped form a hidden carbon sink under the desert

Scientists have found a potentially large carbon sink in the most unlikely place on Earth – under the desert. The increase in carbon storage is linked with the rise of farming in arid landscapes.

This surprising conclusion comes from work done in the Tarim Basin of western China by Chinese and American scientists. The results are published in the journal Geophysical Research Letters.

“Basically, people thought the whole arid region is totally negligible to the global carbon budget,” says lead author Yan Li of the Chinese Academy of Sciences in Urumqi. “We are arguing that that’s not the case.”

Li and colleagues measured and dated the carbon content of water samples taken from a salty aquifer beneath the Tarim Basin. They show that the rate at which carbon sunk into the aquifer rose dramatically with the rise of farming and agriculture in the region. Rate of carbon storage increased by more than 12 times previous levels over the past 8000 years with particularly high levels beginning around 2000 years ago when the Silk Road opened.

How it works

The process began when humans started to grow crops on sandy soil. As the plants take in carbon dioxide from the air, some is released into the sand. Farming in desert conditions requires a lot of water to combat rising salinity caused by rapidly evaporating water. This organic carbon dissolves in the water and is transported down through the sand into deed salty aquifers.

Li_etal_2015
A schematic diagram showing the leaching and transport of DIC (dissolved inorganic carbon) in a closed arid basin. Source: Li et al, 2015

Normally these aquifers are tapped by rivers and streams and so the carbon comes back out of storage. But in the Tarim Basin the aquifer is a closed system, meaning that water does not escape, effectively locking away the carbon.

Li expects this process to occur in deserts around the globe but the amount of carbon would vary depending on the pH of the soil and the level of farming activity.

The results from this study will have important implications for the study of the global carbon cycle as desert regions were previously thought to be unimportant for carbon storage.

Read the full study here: http://onlinelibrary.wiley.com/doi/10.1002/2015GL064222/abstract

Will we lose our crops to climate change?

With the World’s population now past 7 billion and projected to increase to 9 billion by 2050, stress on the food production system is at an all time high. To make matters worse it appears that our crop yields may fall victim to the effects of climate change.

Crop yields to drop by 25 percent towards the second half of the century.
Crop yields to drop by 25 percent towards the second half of the century.

Global warming of only 2°C will be detrimental to the production of rice, wheat and maize in temperate and tropical regions, with reduced yields from the 2030s onwards claims a study, published in Nature Climate Change last year, led by the University of Leeds scientists.

“Climate change means a less predictable harvest, with different countries winning and losing in different years. The overall picture remains negative, and we are now starting to see how research can support adaptation by avoiding the worse impacts,” says lead author Professor Andy Challinor.

The study shows that we will see, on average, an increasingly negative impact of climate change on crop yields from the 2030s onwards. The impact will be greatest in the second half of the century, when decreases of over 25% will become increasingly common.

These statistics already account for minor adaptation techniques employed by farmers to mitigate the effects of climate change, such as small adjustments in crop variety and planting date.

The IPCC projected temperature increase for the next century.
The IPCC projected temperature increase for the next century.

The latest Inter-governmental Panel on Climate Change (IPCC) reports state that the expected temperature increase for the end of the century is somewhere between 1.5 and 4 degree Celsius. And thus, major agricultural transformations and innovations will be needed in order to safeguard crop yields for future generations.

Read the full study here: http://www.nature.com/nclimate/journal/v4/n4/full/nclimate2153.html