Here are 10 stories showing how the importance of proper understanding of Earth science has either been lacking and resulted in an avoidable disaster, or been properly employed to good effect.
12-13 February 2008
UNESCO Headquarters (Entrance 125 Avenue de Suffren, 75007 Paris, France)
The Vajont reservoir disaster is a classic example of the consequences of the failure of engineers and geologists to understand the nature of the problem that they were trying to deal with.
During the filling of the reservoir a block of approximately 270 million cubic metres detached from one wall and slid into the lake at velocities of up to 30 metres per second (approx. 110 kilometres per hour).
As a result a wave overtopped the dam by 250m and swept onto the valley below, with the loss of about 2500 lives.
The dam remained unbroken by the flood and is still there today.
Proper understanding of the geology of the hillside would have prevented the disaster.
Vajont is located in the south-eastern part of the Dolomite Region of the Italian Alps, about 100km north of Venice. It was built as a part to provide hydroelectricity for the rapidly-expanding northern cities of Milan, Turin and Modena.
A proposal to site a dam at this location was made in the 1920s; excavation of the site began in 1956 and the dam was completed in 1960.
The completed doubly curved arch dam was, at 265.5 metres above the valley floor, the world’s highest thin arch dam. The volume of impounded water was 115 million cubic metres.
On the evening of 20 September 2002, the Kolka glacier collapsed and plunged 24km down into the Genaldon Gorge.
Locals believe as many as 300 people may have been killed – a death toll that could have been avoided by proper monitoring of the glacier. The area had not been studied for more than a decade.
The collapsing glacier sped down the mountains at around 150km an hour, and buried the village of Karmadon and adjacent holidaying areas under a 50m thick layer of stones and ice.
Local geologists estimated that the debris may have comprised between 80 and 150 million tons of rock and costing c. 15-17 million US dollars, according to early reports.
The glacier’s first movement was registered in 1885. Seventeen years later, heavy rains and an intense thaw caused it to slide over a distance of 12km, causing a violent mudflow which wrecked the village of Genal and the Tmenikau resort, killing many people.
North Ossetia’s scientists frequently spoke of the need to set up a research institute to study ice flow developments in mountainous areas.
It is believed such a programme could have helped them forecast large-scale natural catastrophes such as Kolka, preventing loss of life.
Before 2002, the last time Kolka had shifted was in 1969. While the glacier moved less than four kilometres, residents of Gizel were evacuated as a precaution.
Following this, a group of glaciologists was set up to monitor the glaciers of the North Caucasus – but later broke up for lack of funding.
The magnitude 9 earthquake that struck the southern coast of Sumatra, Indonesia on 26 December 2004 resulted in for first "Global Geophysical Event" since the eruption of Krakatoa in 1883.
Almost a quarter of a million people died, mostly around the Indian Ocean coasts that were ravaged by the resulting tsunami.
The Pacific Ocean, which is itself surrounded by destructive plate margins where the Pacific sea floor is being overridden by the continents, is also prone to large earthquakes and tsunamis.
However there, an early warning system, combined with an international programme of education and training and well-established drills for acting upon warnings received, has saved thousands of lives since it was first set up by the US immediately following World War 2.
The geophysical tools to enable tsunami early warning existed but were not deployed in the Indian Ocean, which is of course surrounded by much poorer countries than the Pacific.
Now, a system modelled on the Pacific one is in place; however it will prove useless without the political will to educate the populations around the Indian Ocean – highlighting the fact that science alone is not enough.
There must also be social and educational infrastructure in place as well.
Flooding causes more death and destruction of property worldwide than any other single form of natural disaster. Yet most of the deaths that occur do so because of a combination of a) lack of advice about wise places to build b) poor or non-existent mitigation strategies in flood-prone regions c) ill-advised actions upstream (denudation, building, canalization) that deliver more water more quickly to downstream areas.
Rivers often traverse national boundaries, which means that decisions in one country need to be made with other countries’ needs in mind - demanding international cooperation that has been slow to materialise.
In 2004 the World Bank said in a report on the cost of the natural disasters of the 1990s that $40 billion spent on risk reduction and preparation could have cut that decade’s final bill in half - from $535 billion to $255 billion. The Bank also estimated that in the forty previous years, $3.15 billion invested in flood control by China averted losses of $12 billion.
Such strategies are most effective when dealing with floods. China’s flood casualties have dropped throughout the century, partly though increased investment in protection and evacuation planning. During the 1930s and 40s, 4.4 million people died from flooding in China.
In the next two decades that number fell to 2 million, and by the 1970s and 80s it was down to 14,000.
But flooding is not a problem confined to the developing world. While lives are rarely lost to floods in same degree, economic losses in developed nations are increasing as floods become more frequent (possibly a symptom of global warming and increased "storminess", but also to do with canalization, denudation of watersheds and the spread of impermeable man-made surfaces).
Adding to this is rising pressure for new building land. Planners often turn to the flat expanses of river floodplains.
River floodplains exist to absorb excess runoff – they are meant to flood. Building on them, and reinforcing riverbanks to protect the development, merely sends yet more water downstream – displacing the problem first, and then ultimately failing themselves. The unwisdom of such developments is rooted in a failure to apply long-established hydrological and hydrogeological knowledge to planning decisions.
On 13 November, 1985, the volcano known as Nevado del Ruiz erupted. Pyroclastic flows melted ice and snow at the summit, and the resulting water mobilised the poorly consolidated volcanic ash on the volcano to form mudflows – known as "lahars" - that rushed down several river valleys draining the volcano slopes.
The lahars were up to 50 metres deep and many travelled more than 100 kilometres.
The town of Armero was completely covered by debris, killing approximately 21,000 people (out of a total population of about 28,700). The eruption was the second most deadly volcanic disaster of the 20th Century (the 1902 eruption of Mount Pelée, Martinique, was the worst).
The villagers were warned about the possibility of the disaster but because of past false information and conflicting messages from local political leaders that contradicted the scientific advice, many people did not believe the warnings.
A hazard risk map of the region, produced some months before by the Colombian Geological Survey, was reportedly not used. This was a classic example of inadequate regard being given to the warnings issued by Earth scientists.
For more on the deadly lahars of Nevado del Ruiz, 1985:
Capturing carbon and locking it safely away underground is a new technique that offers huge potential for meeting emissions targets and deflecting the imminent threat of global warming. However it can also help improve the yield of oil reservoirs.
Oil reservoirs are often under pressure, and when first pierced used to "gush", before technology consigned this spectacular phenomenon to the history books.
Initial pressure soon reduces however and soon pumping becomes necessary.
Reservoir pressure may be driven by a rising aquifer underneath the oil, but often water has to be pumped down below the oil to force it out.
This process involves pumping CO2 into an oil reservoir, increasing the reservoir pressure and allowing CO2 to dissolve into the oil and so reduce its viscosity and increase its volume.
All of these effects allow oil to flow out more easily.
This method is used extensively in older fields where the original reservoir pressure has been lost.
CO2 is pumped into the reservoir through an ‘injection well’ forcing oil towards a ‘production well’ where it is pumped to the surface. In most commercial onshore oil fields the CO2 is extracted at the surface and is then re-injected back into the reservoir.
The CO2 is then left and stored within the oil reservoir, thus improving yield and reducing carbon emissions. Carbon capture potentially allows the continued use of gas and coal, whilst still meeting ambitious CO2 reduction targets.
Scottish Centre for Carbon Storage
How old wells can still make a contribution
Web article on EOR and carbon capture
Radon is an inert gas. It is not poisonous, but is a problem in the environment because it is radioactive, cannot be seen, heard or felt, and is all around us.
Radon is created when the element uranium and thorium undergo radioactive decay.
These elements are more common in some rocks than others, so radon varies in concentration according to the geology. These are typically areas underlain by acid igneous rocks like granite, dark shales rich in organic matter, and rocks rich in phosphate minerals.
Radon emits high energy alpha particles, which can damage genetic material and cause cancer. There is therefore a higher cancer risk in areas where radon is present in greater abundance in the underlying rocks. It is thought that between 2000 and 3000 people in the UK die through natural radon-induced lung cancer every year.
Since this link was discovered, geoscientists worldwide have devised advice and guidance on which areas estimated to contain homes exceeding the required action levels – these mirror the geological map very closely. Houses in these areas act as traps for radon gas, and must be adequately ventilated to reduce the risk to acceptable levels.
This is particularly true for cellar areas. Authorities with jurisdiction over these areas are then able to implement proper procedures, warning householders of the danger and advising on the best course of action to prevent dangerous build-ups.
In the UK as in other countries this is one of the best examples of how geoscientific advice can lead, through effective policy implementation, to a great improvement in quality of life.
See "Radon", no. 5 of the general information sheets referred to below under the series title "The Earth in our hands".
We all know that rocks can kill us by landing on our heads, but rocks often have a much greater influence on our health than we realise (see 7 for an example). Dust is usually thought of by westerners as the cause of industrial diseases like silicosis and asbestosis. However in many parts of the world these same diseases occur among the general population. "Non-occupational" silicosis in China, with its dusty climate caused by wind-blown rockflour created by the glaciers of the Himalayas, is a common health problem unknown in less dusty climates.
Asbestosis - cancer caused by inhaling dust formed by friable fibrous minerals - has been occurring in the Cappadocia region of Eastern Turkey for thousands of years.
There, the rare cancer mesothelioma could (in some clusters) be so common a cause of death that even names of villages reflected its common symptoms.
These clusters of mesothelial cancer were discovered as recently as 1975, among peoples who inhabited caves carved into soft, weathered volcanic ash deposits. Since being laid down in huge thicknesses from a nearby volcano, these deposits have been eroded into fantastical tepee-shaped masses into which the dwellings are cut – and which are now a great tourist attraction. The problem is – these weathered ashes contain a mineral called erionite, which is the most virulent known promoter of mesothelial cancers.
These people were not only breathing dust – they were living in it, drinking it and eating it.
Discovery of the dangers of living in troglodyte homes led to evacuation and resettlement programmes. Subsequent studies have also revealed that the environmental medical situation in Cappadocia is complex. Many of the unfortunate inhabitants of the region are also victims of a genetic predisposition to this particular form of cancer, which helps explain the anomalously large clusters of this normally very rare disease.
The Toxic Potential of Mineral Dusts by Fubini and Fenoglio:
The Earth is a source of inexhaustible heat, generated mostly by natural radioactivity in the rocks beneath us. Heat escapes from the planet everywhere, but some areas have a higher heat flow than others, and this makes them ideal for certain types of geothermal power plant.
Geothermal energy offers a number of advantages over traditional fossil fuel.
The energy harnessed is clean and safe for the surrounding environment. It is also sustainable because the hot water used in the geothermal process can be re-injected into the ground. In addition, geothermal power plants are unaffected by weather conditions; they work continually, making them suitable as "base load" power plants.
Geothermal energy is competitive in some areas and reduces reliance on fossil fuels.
Geothermal plants are also efficient at different scales: a large geothermal plant can power an entire city while smaller power plants can supply more remote sites.
There are several different sorts of geothermal power plant; but all rely on deep-seated heat flow.
Another source of heat, now increasingly being used for domestic heating where enough land available, is a Ground Source Heat Pump – of which there are also several different kinds. The energy of the sun is absorbed by the ground and can be extracted by a heat exchanger (often covering many hectares) consisting of underground pipes.
Taken together, geothermal heat is now beginning to provide a valuable contribution to the mix of renewables that will be needed to plug the world’s looming energy gap.
The Canadian Geoexchange Coalition
Geothermal Heat Pumps
International Ground Source Heat Pump Association
BBC page on Geothermal Energy
The inhabitants of Zimapàn, Mexico, live with water supplies that are contaminated with arsenic (As), but cannot afford commercially available domestic purifying systems. In 2001 geoscientists revealed that the answer lay all around them. Zimapàn, 200km north of Mexico City, has been a mining district since the 16th Century. Lead, silver and zinc have been extracted from mineralised ores related to Tertiary-age igneous intrusions.
These natural sources contaminate some water supplies, while others may be polluted by modest quantities of rainwater leaching through mine tailings. Some tailing leachates have As concentrations of almost 16 g/litre.
About half of the water supplies samples tested by Mexico’s National Water Commission have As concentrations above current WHO guidelines (0.01mg/litre).
The wells used for municipal water supply are heavily contaminated, and even after dilution from unpolluted water sources, still have concentrations up to about 0.4mg/litre, with likely local health consequences. Over 40% of residents are not connected to this municipal supply and rely on local springs and norias (bucket-wheel wells) for drinking water. Unfortunately many of these are also polluted with As. In a region where 72% of the population earned less than US$3.00/day in 1994, commercial purification systems lay well beyond their reach.
In 1994, the Lois Ongley (Androscoggin Valley Environmental Center, Lewiston, USA) and Aurora Armienta (Instituto di Geofisica, Universidad Nacional Autonoma de Mexico) and others created contaminated water (ECW) by shaking pure water with samples of mine tailings. This was then reacted with samples of various local rocks.
The experiments demonstrate clearly that As is reduced below detectable levels in any sample of ECW that has been mixed with rocks of the local Soyatal Formation.
This Formation, which crops out throughout the area of contamination, is a calcareous shale containing up to 15% clay minerals (kaolinite and illite). Both of these are known to adsorb As. Water sources emerging through the Soyatal Formation are uniformly low in As.
Where commercial purification mechanisms (which use ion exchange to resins, green sand filtration and reverse osmosis) are too expensive, this low-tech mechanism lies well within the pockets of local residents, requiring no more sophisticated equipment than a bucket.
The researchers discovered that one or two kilograms of crushed rock, added to about 20 litres of contaminated water, stirred frequently over 24 hours effectively removed As to below acceptable levels.
Ongley, LK et al., 2001: Arsenic removal from contaminated water by the Soyatal Formation, Zimapàn Mining District, Mexico - a potential low-cost, low-tech remediation system. Geochemistry, Exploration, Environment, Analysis, vol. 1.
Dr Lois Ongley
Tel.: (+001) 207 783 6952)
E-mail: lko AT avec-me.org
Dr Aurora Armienta
Tel.: ( +0052) 5 622 4114
Fax: (+0052) 5 550 2486)
E-mail: victoria AT igeofcu.unam.mx
General information on geological hazards and their avoidance IDNDR-ESCAP Risk Reduction & Society in the 21st Century: Bangkok, 23-26 February 1999.
Geology-related Hazards, Resources and Management for Disaster Reduction in Asia; Water and Mineral Resources Section. (Environment and Natural Resource Development Division Economic and Social Commission for Asia and the Pacific (ESCAP))
General information sheets with internet links on Earthquakes, Flooding, Landslides, Volcanoes, Radon, Tsunamis, Coastal Erosion, Contaminated Land, Landfill & Waste, Groundwater, Aggregates and Marine Aggregates can be downloaded from the website of The Geological Society of London.
All these sheets come from a series entitled "The Earth in our Hands" and are downloadable here:
International Year of Planet Earth Inc.
E-mail: iype.secretariat AT ngu.no