Earth’s oldest known impact crater found in Greenland

A 100 kilometer-wide crater has been found in Greenland, the result of a massive asteroid or comet impact a billion years before any other known collision on Earth.

The spectacular craters on the Moon formed from impacts with asteroids and comets between 3 and 4 billion years ago. The early Earth, with its far greater gravitational mass, must have experienced even more collisions at this time – but the evidence has been eroded away or covered by younger rocks. The previously oldest known crater on Earth formed 2 billion years ago and the chances of finding an even older impact were thought to be, literally, astronomically low.

Now, a team of scientists from the Geological Survey of Denmark and Greenland (GEUS) in Copenhagen, Cardiff University in Wales, Lund University in Sweden and the Institute of Planetary Science in Moscow has upset these odds. Following a detailed programme of fieldwork, funded by GEUS and the Danish ‘Carlsbergfondet’ (Carlsberg Foundation), the team have discovered the remains of a giant 3 billion year old impact near the Maniitsoq region of West Greenland.

“This single discovery means that we can study the effects of cratering on the Earth nearly a billion years further back in time than was possible before,” according to Dr Iain McDonald of Cardiff University’s School of Earth and Ocean Sciences, who was part of the team.

Finding the evidence was made all the harder because there is no obvious bowl-shaped crater left to find. Over the 3 billion years since the impact, the land has been eroded down to expose deeper crust 25 km below the original surface. All external parts of the impact structure have been removed, but the effects of the intense impact shock wave penetrated deep into the crust – far deeper than at any other known crater – and these remain visible.

However, because the effects of impact at these depths have never been observed before it has taken nearly three years of painstaking work to assemble all the key evidence. “The process was rather like a Sherlock Holmes story,” said Dr McDonald. “We eliminated the impossible in terms of any conventional terrestrial processes, and were left with a giant impact as the only explanation for all of the facts.”

Only around 180 impact craters have ever been discovered on Earth and around 30% of them contain important natural resources of minerals or oil and gas. The largest and oldest known crater prior to this study, the 300 kilometre wide Vredefort crater in South Africa, is 2 billion years in age and heavily eroded.

Dr McDonald added that “It has taken us nearly three years to convince our peers in the scientific community of this but the mining industry was far more receptive. A Canadian exploration company has been using the impact model to explore for deposits of nickel and platinum metals at Maniitsoq since the autumn of 2011.”

The international team was led by Adam A. Garde, senior research scientist at GEUS. The first scientific paper documenting the discovery has just been published in the journal Earth and Planetary Science Letters.

Earth’s oldest known impact crater found in Greenland

A 100 kilometer-wide crater has been found in Greenland, the result of a massive asteroid or comet impact a billion years before any other known collision on Earth.

The spectacular craters on the Moon formed from impacts with asteroids and comets between 3 and 4 billion years ago. The early Earth, with its far greater gravitational mass, must have experienced even more collisions at this time – but the evidence has been eroded away or covered by younger rocks. The previously oldest known crater on Earth formed 2 billion years ago and the chances of finding an even older impact were thought to be, literally, astronomically low.

Now, a team of scientists from the Geological Survey of Denmark and Greenland (GEUS) in Copenhagen, Cardiff University in Wales, Lund University in Sweden and the Institute of Planetary Science in Moscow has upset these odds. Following a detailed programme of fieldwork, funded by GEUS and the Danish ‘Carlsbergfondet’ (Carlsberg Foundation), the team have discovered the remains of a giant 3 billion year old impact near the Maniitsoq region of West Greenland.

“This single discovery means that we can study the effects of cratering on the Earth nearly a billion years further back in time than was possible before,” according to Dr Iain McDonald of Cardiff University’s School of Earth and Ocean Sciences, who was part of the team.

Finding the evidence was made all the harder because there is no obvious bowl-shaped crater left to find. Over the 3 billion years since the impact, the land has been eroded down to expose deeper crust 25 km below the original surface. All external parts of the impact structure have been removed, but the effects of the intense impact shock wave penetrated deep into the crust – far deeper than at any other known crater – and these remain visible.

However, because the effects of impact at these depths have never been observed before it has taken nearly three years of painstaking work to assemble all the key evidence. “The process was rather like a Sherlock Holmes story,” said Dr McDonald. “We eliminated the impossible in terms of any conventional terrestrial processes, and were left with a giant impact as the only explanation for all of the facts.”

Only around 180 impact craters have ever been discovered on Earth and around 30% of them contain important natural resources of minerals or oil and gas. The largest and oldest known crater prior to this study, the 300 kilometre wide Vredefort crater in South Africa, is 2 billion years in age and heavily eroded.

Dr McDonald added that “It has taken us nearly three years to convince our peers in the scientific community of this but the mining industry was far more receptive. A Canadian exploration company has been using the impact model to explore for deposits of nickel and platinum metals at Maniitsoq since the autumn of 2011.”

The international team was led by Adam A. Garde, senior research scientist at GEUS. The first scientific paper documenting the discovery has just been published in the journal Earth and Planetary Science Letters.

A new method accounts for social factors when assessing the seismic risk of a city

This is a building in the city of Lorca in Murcia after the earthquake. -  Lorca 072
This is a building in the city of Lorca in Murcia after the earthquake. – Lorca 072

Seismic risk not only depends on the magnitude of the tremor itself but also on the resistance of buildings and the social characteristics of its population. A team of Spanish scientists have presented a new method for calculating seismic risk incorporating aspects like social fragility and the chances of collective recovery.

“When faced with the possibility of an earthquake, up until now the physical risk of the city has only ever been evaluated. This, in other words, means damage to buildings and infrastructures taking into consideration the amount of people inside,” as explained to SINC by Liliana Carreño, researcher at the Polytechnic University of Catalonia (UPC). Her team proposes a new method of carrying out an overall assessment of the seismic risk of an urban area, taking into account the social strengths and weakness and the city’s governance.

The system created by Carreño and her team considers values such as “crime rates, whether there are marginalized areas, the number of hospital beds, training of hospital staff, etc, which all constitute factors of fragility and social capacity,” explain the researchers. “This methodology greatly improves on our ability to assess future losses because it takes into account the social condition of the exposed population, which was previously treated as a mere number,” states Carreño.

Published in the Bulletin of Earthquake Engineering, the new approach has another added value: it uses a technique based on ‘fuzzy logic theory’ which allows for the use of qualitative information obtained from expert opinion when the necessary numerical information is lacking.

Translating Opinions to Numbers

“The methods for making a complete risk calculation in a given urban area require great quantities of information that is not always available” highlights the researcher. According to Carreño, seismic risk specialists have always faced complex problems concerning imprecise information. “We can now translate linguistic variables like a lot, a few, slight, severe, scarce and enough into mathematic formalism for their subsequent measurement,” outlines the scientist.

In order to verify the method’s validity, Carreño and her team applied it to the cities of Barcelona and Bogotá (Colombia). She adds that “the Catalan city is a good model since its seismic risk has been subject to study for more than 20 year.” Its results confirmed expected risk levels: medium-high for Bogotá and medium-low for Barcelona.

As Carreño concludes, “Barcelona’s assessment was carried out with the availability of sound information. But, the most important aspect of this model is that it is especially useful when studying an urban space that does not have such an advantage and where information is lacking.”

A new method accounts for social factors when assessing the seismic risk of a city

This is a building in the city of Lorca in Murcia after the earthquake. -  Lorca 072
This is a building in the city of Lorca in Murcia after the earthquake. – Lorca 072

Seismic risk not only depends on the magnitude of the tremor itself but also on the resistance of buildings and the social characteristics of its population. A team of Spanish scientists have presented a new method for calculating seismic risk incorporating aspects like social fragility and the chances of collective recovery.

“When faced with the possibility of an earthquake, up until now the physical risk of the city has only ever been evaluated. This, in other words, means damage to buildings and infrastructures taking into consideration the amount of people inside,” as explained to SINC by Liliana Carreño, researcher at the Polytechnic University of Catalonia (UPC). Her team proposes a new method of carrying out an overall assessment of the seismic risk of an urban area, taking into account the social strengths and weakness and the city’s governance.

The system created by Carreño and her team considers values such as “crime rates, whether there are marginalized areas, the number of hospital beds, training of hospital staff, etc, which all constitute factors of fragility and social capacity,” explain the researchers. “This methodology greatly improves on our ability to assess future losses because it takes into account the social condition of the exposed population, which was previously treated as a mere number,” states Carreño.

Published in the Bulletin of Earthquake Engineering, the new approach has another added value: it uses a technique based on ‘fuzzy logic theory’ which allows for the use of qualitative information obtained from expert opinion when the necessary numerical information is lacking.

Translating Opinions to Numbers

“The methods for making a complete risk calculation in a given urban area require great quantities of information that is not always available” highlights the researcher. According to Carreño, seismic risk specialists have always faced complex problems concerning imprecise information. “We can now translate linguistic variables like a lot, a few, slight, severe, scarce and enough into mathematic formalism for their subsequent measurement,” outlines the scientist.

In order to verify the method’s validity, Carreño and her team applied it to the cities of Barcelona and Bogotá (Colombia). She adds that “the Catalan city is a good model since its seismic risk has been subject to study for more than 20 year.” Its results confirmed expected risk levels: medium-high for Bogotá and medium-low for Barcelona.

As Carreño concludes, “Barcelona’s assessment was carried out with the availability of sound information. But, the most important aspect of this model is that it is especially useful when studying an urban space that does not have such an advantage and where information is lacking.”

Scientists compile first study of potential for tsunamis in northwestern California

Using studies that span the last three decades, scientists at UC Santa Barbara have compiled the first evidence-based comprehensive study of the potential for tsunamis in Northwestern California. The paper, “Paleoseismicity of the Southern End of the Cascadia Subduction Zone, Northwestern California,” was co-written by professors Edward Keller and Alexander Simms from UCSB’s Department of Earth Science, and published in a recent issue of the Bulletin of the Seismological Society of America.

The paper is based on the Ph.D. dissertation of David Valentine, a research programmer at the Spatial Information Systems Laboratory at UC San Diego. Valentine, Keller’s former student, completed his doctorate at UCSB in 2002 and is first author of the paper.

The region has long been known to experience large earthquakes, and scientific studies of seismic activity in the southern end of the Cascadia Subduction Zone (CSZ) — which stretches northward from the area of Mendocino, Calif. — have previously appeared in grey literature and in guidebooks. However, comprehensive, reviewed evidence-based work has been lacking, according to Keller.

“Science goes on evidence,” he said, adding that in light of the recent earthquakes in Japan and Chile, the study of the same potential closer to home is “timely.” The authors studied sedimentation patterns in salt marshes, floodplains, and estuaries in the northwestern corner of California for signs of seismic events that could lead to tsunami activity. They combined this with information gathered from numerous studies conducted over nearly 30 years by researchers at Humboldt State University

During an earthquake, the researchers say, there is a tendency for the coastal wetlands to become submerged, with coastal sediments depositing over plants and animals that live there. These become a fossilized record of sea-level change in the area.

The process has preserved a sequence of marsh surfaces and forest soils. Analysis of structure, texture, and organic content, as well as the use of radiocarbon dating to identify the age of the materials, revealed evidence of smaller strong-to-major earthquakes in the area (magnitude 6.5 to 7.2). Larger quakes (greater than magnitude 8.2) that involved the regional subduction zone, were also in evidence.

According to the study, the local California section has experienced three major earthquakes over the last 2000 years, and accompanying local sea-level changes at roughly 300- to 400-year intervals, with the last one occurring 500 to 600 years ago. The researchers also found that the entire CSZ erupted, causing local submergence at least three times in roughly 500- to 600- year intervals, the last activity taking place in 1700 AD.

“It’s not a matter of if, but when,” said Keller, of the potential for the next major earthquake/tsunami event in the region — a great earthquake that would impact not only the Northwest, but also send waves to Japan and Hawaii. The evidence, he said, is leading to far more foresight and planning along the impact areas in the region to avoid catastrophes on a level with the Japan earthquake of 2011 or the Indian Ocean quake of 2004.

Scientists compile first study of potential for tsunamis in northwestern California

Using studies that span the last three decades, scientists at UC Santa Barbara have compiled the first evidence-based comprehensive study of the potential for tsunamis in Northwestern California. The paper, “Paleoseismicity of the Southern End of the Cascadia Subduction Zone, Northwestern California,” was co-written by professors Edward Keller and Alexander Simms from UCSB’s Department of Earth Science, and published in a recent issue of the Bulletin of the Seismological Society of America.

The paper is based on the Ph.D. dissertation of David Valentine, a research programmer at the Spatial Information Systems Laboratory at UC San Diego. Valentine, Keller’s former student, completed his doctorate at UCSB in 2002 and is first author of the paper.

The region has long been known to experience large earthquakes, and scientific studies of seismic activity in the southern end of the Cascadia Subduction Zone (CSZ) — which stretches northward from the area of Mendocino, Calif. — have previously appeared in grey literature and in guidebooks. However, comprehensive, reviewed evidence-based work has been lacking, according to Keller.

“Science goes on evidence,” he said, adding that in light of the recent earthquakes in Japan and Chile, the study of the same potential closer to home is “timely.” The authors studied sedimentation patterns in salt marshes, floodplains, and estuaries in the northwestern corner of California for signs of seismic events that could lead to tsunami activity. They combined this with information gathered from numerous studies conducted over nearly 30 years by researchers at Humboldt State University

During an earthquake, the researchers say, there is a tendency for the coastal wetlands to become submerged, with coastal sediments depositing over plants and animals that live there. These become a fossilized record of sea-level change in the area.

The process has preserved a sequence of marsh surfaces and forest soils. Analysis of structure, texture, and organic content, as well as the use of radiocarbon dating to identify the age of the materials, revealed evidence of smaller strong-to-major earthquakes in the area (magnitude 6.5 to 7.2). Larger quakes (greater than magnitude 8.2) that involved the regional subduction zone, were also in evidence.

According to the study, the local California section has experienced three major earthquakes over the last 2000 years, and accompanying local sea-level changes at roughly 300- to 400-year intervals, with the last one occurring 500 to 600 years ago. The researchers also found that the entire CSZ erupted, causing local submergence at least three times in roughly 500- to 600- year intervals, the last activity taking place in 1700 AD.

“It’s not a matter of if, but when,” said Keller, of the potential for the next major earthquake/tsunami event in the region — a great earthquake that would impact not only the Northwest, but also send waves to Japan and Hawaii. The evidence, he said, is leading to far more foresight and planning along the impact areas in the region to avoid catastrophes on a level with the Japan earthquake of 2011 or the Indian Ocean quake of 2004.

Scientists find new primitive mineral in meteorite

Panguite is embedded in a piece of the Allende meteorite. -  Chi Ma / Caltech
Panguite is embedded in a piece of the Allende meteorite. – Chi Ma / Caltech

In 1969, an exploding fireball tore through the sky over Mexico, scattering thousands of pieces of meteorite across the state of Chihuahua. More than 40 years later, the Allende meteorite is still serving the scientific community as a rich source of information about the early stages of our solar system’s evolution. Recently, scientists from the California Institute of Technology (Caltech) discovered a new mineral embedded in the space rock-one they believe to be among the oldest minerals formed in the solar system.

Dubbed panguite, the new titanium oxide is named after Pan Gu, the giant from ancient Chinese mythology who established the world by separating yin from yang to create the earth and the sky. The mineral and the mineral name have been approved by the International Mineralogical Association’s Commission on New Minerals, Nomenclature and Classification. A paper outlining the discovery and the properties of this new mineral will be published in the July issue of the journal American Mineralogist, and is available online now.

“Panguite is an especially exciting discovery since it is not only a new mineral, but also a material previously unknown to science,” says Chi Ma, a senior scientist and director of the Geological and Planetary Sciences division’s Analytical Facility at Caltech and corresponding author on the paper.

The Allende meteorite is the largest carbonaceous chondrite-a diverse class of primitive meteorites-ever found on our planet and is considered by many the best-studied meteorite in history. As a result of an ongoing nanomineralogy investigation of primitive meteorites-which Ma has been leading since 2007-nine new minerals, including panguite, have been found in the Allende meteorite. Some of those new finds include the minerals allendeite, hexamolybdenum, tistarite, and kangite. Nanomineralogy looks at tiny particles of minerals and the minuscule features within those minerals.

“The intensive studies of objects in this meteorite have had a tremendous influence on current thinking about processes, timing, and chemistry in the primitive solar nebula and small planetary bodies,” says coauthor George Rossman, the Eleanor and John R. McMillan Professor of Mineralogy at Caltech.

Panguite was observed first under a scanning electron microscope in an ultra-refractory inclusion embedded in the meteorite. Refractory inclusions are among the first solid objects formed in our solar system, dating back to before the formation of Earth and the other planets. “Refractory” refers to the fact that these inclusions contain minerals that are stable at high temperatures and in extreme environments, which attests to their likely formation as primitive, high-temperature liquids produced by the solar nebula.

According to Ma, studies of panguite and other newly discovered refractory minerals are continuing in an effort to learn more about the conditions under which they formed and subsequently evolved. “Such investigations are essential to understand the origins of our solar system,” he says.

Scientists find new primitive mineral in meteorite

Panguite is embedded in a piece of the Allende meteorite. -  Chi Ma / Caltech
Panguite is embedded in a piece of the Allende meteorite. – Chi Ma / Caltech

In 1969, an exploding fireball tore through the sky over Mexico, scattering thousands of pieces of meteorite across the state of Chihuahua. More than 40 years later, the Allende meteorite is still serving the scientific community as a rich source of information about the early stages of our solar system’s evolution. Recently, scientists from the California Institute of Technology (Caltech) discovered a new mineral embedded in the space rock-one they believe to be among the oldest minerals formed in the solar system.

Dubbed panguite, the new titanium oxide is named after Pan Gu, the giant from ancient Chinese mythology who established the world by separating yin from yang to create the earth and the sky. The mineral and the mineral name have been approved by the International Mineralogical Association’s Commission on New Minerals, Nomenclature and Classification. A paper outlining the discovery and the properties of this new mineral will be published in the July issue of the journal American Mineralogist, and is available online now.

“Panguite is an especially exciting discovery since it is not only a new mineral, but also a material previously unknown to science,” says Chi Ma, a senior scientist and director of the Geological and Planetary Sciences division’s Analytical Facility at Caltech and corresponding author on the paper.

The Allende meteorite is the largest carbonaceous chondrite-a diverse class of primitive meteorites-ever found on our planet and is considered by many the best-studied meteorite in history. As a result of an ongoing nanomineralogy investigation of primitive meteorites-which Ma has been leading since 2007-nine new minerals, including panguite, have been found in the Allende meteorite. Some of those new finds include the minerals allendeite, hexamolybdenum, tistarite, and kangite. Nanomineralogy looks at tiny particles of minerals and the minuscule features within those minerals.

“The intensive studies of objects in this meteorite have had a tremendous influence on current thinking about processes, timing, and chemistry in the primitive solar nebula and small planetary bodies,” says coauthor George Rossman, the Eleanor and John R. McMillan Professor of Mineralogy at Caltech.

Panguite was observed first under a scanning electron microscope in an ultra-refractory inclusion embedded in the meteorite. Refractory inclusions are among the first solid objects formed in our solar system, dating back to before the formation of Earth and the other planets. “Refractory” refers to the fact that these inclusions contain minerals that are stable at high temperatures and in extreme environments, which attests to their likely formation as primitive, high-temperature liquids produced by the solar nebula.

According to Ma, studies of panguite and other newly discovered refractory minerals are continuing in an effort to learn more about the conditions under which they formed and subsequently evolved. “Such investigations are essential to understand the origins of our solar system,” he says.

New book looks at hotspots around the world for mega-quakes

This is a high school running track in Taiwan crossed by the Chelungpu fault in an earthquake in September 1999. -  Bob Yeats, Oregon State University.
This is a high school running track in Taiwan crossed by the Chelungpu fault in an earthquake in September 1999. – Bob Yeats, Oregon State University.

At the beginning of 2010, Oregon State University geologist Bob Yeats told a national reporter that Port au Prince, Haiti, was a “time bomb” for a devastating earthquake because of its crowded, poorly constructed buildings and its proximity to the Enriquillo Fault.

One week later, a magnitude 7 earthquake destroyed Port au Prince, killing hundreds of thousands of people and devastating the economy of Haiti.

The clock is ticking on many other earthquake faults throughout the world, Yeats says, and though he did not “predict” the Haiti earthquake, he can point to other places that could face the same fate. He outlines some of these areas in a new book called “Active Faults of the World,” published by Cambridge University Press.

“We are not yet to the point where we can predict earthquakes,” said Yeats, a professor emeritus in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “What we can do is tell you where some of the most dangerous faults lie – and where those coincide with crowded cities, few building codes, and a lack of social services, you have a time bomb.

“Unfortunately, we can’t say if an earthquake will strike today, tomorrow or in a hundred years,” he added. “But in all of these locations it will happen someday – and unless something is done to improve conditions, many thousands of people will die.”

In his book, Yeats notes that the greatest migration in human history is of people moving from rural areas to “megacities” in the developing world. People have flocked to these mega-cities where multi-level housing and businesses are rapidly built, and often poorly constructed and poorly inspected. When many of these locations last had a major earthquake, their population was small and a majority of the people was living in one-story dwellings, limiting the loss of life.

Yeats cites as an example Caracas, Venezuela, which has an earthquake plate-boundary fault north of the city. In 1812, a major quake shook Caracas and other Venezuelan cities and killed an estimated 10,000 people – about 10 percent of the population at that time. Today, the population of Caracas is nearly 3 million, but government decision-makers are “not placing earthquake hazards high on their list of priorities,” Yeats said, despite the presence of knowledgeable local experts.

Another city near the top of Yeats’ list of earthquake dangers is Kabul, Afghanistan, which suffered an enormous earthquake in 1505. Because of recent wars, the buildings in Kabul are in poor shape – either poorly constructed, or damaged from bombs. On a visit to Kabul in 2002, Yeats found many families living in the ruins of these buildings.


“If Kabul has a repeat of the 1505 earthquake,” Yeats said, “it could kill more people than have died in all of Afghanistan’s wars in the last 40 years because of the influx of refugees living in crowded, substandard conditions.”

Tehran, Iran, is another heavily populated city situated near a major fault line. Located at the base of the Alborz mountain range, Tehran has some 11 million people in its urban boundaries, and Yeats said they are vulnerable because of poorly constructed housing in many parts of the city – a result of corruption in building construction and building inspection industries.

Other over-populated cities near fault lines with poor building codes on Yeats’ list include Istanbul, Turkey, now under an earthquake hazard warning after a quake of magnitude 7.4 in 1999; Nairobi, Kenya, close to a 7.3 quake in the 1920s; and Guantánamo, Cuba.

“Guantánamo is a bit like Haiti,” Yeats pointed out. “They have a fault just offshore, and yet they have no clue they are at risk because Cuba has not had any catastrophic earthquakes in its 500-year history. The military prison operated by the United States would also be at risk, but as far as I know, the Americans are not contributing their expertise to help Guantånamo prepare for its future earthquake.”

There are many places around the world likely to experience a major earthquake in the future, Yeats says, but the “risk” to human lives may not be as high because of less crowding and better building codes. He points to the 2011 super-quake in Japan, which reached a magnitude of 9.0, yet did not cause nearly as much destruction as the tsunami it triggered.

“The Japanese,” Yeats said, “lead the world in taking earthquake risk seriously.”

Yeats was one of the first geologists to point to the Pacific Northwest as being at risk for a major earthquake, because of its proximity to the Cascadia Subduction Zone. Since he and other OSU scientists first raised awareness of that risk in the 1980s, there has been gradual acceptance that an earthquake will strike in the future.

“But will this acceptance lead to concrete action, such as approving a bond issue for seismic upgrades to old school buildings?” Yeats said. “Will it lead to strengthening communities on the West Coast against tsunamis?”

The OSU professor emeritus hopes his book leads to more awareness of the hundreds of faults around the world – some well-known, and some not. This is the first time someone has attempted to summarize the totality of earthquake faults, and Yeats used his own research and observations, as well as exhaustive literature reviews.

“Knowing about the faults is the first step,” Yeats said, “but preparing for the risk is what really needs to happen. It is kind of interesting that Japan has done a lot of work preparing for an earthquake in their Home Islands, and then one bigger than they expected hits northern Japan, accompanied by a devastating tsunami, whose effects have been felt as far away as Oregon.”

A similar thing happened northeast of Beijing, China, in 1976, when a magnitude 7.8 earthquake struck along a fault line that was not thought to be a major threat, killing more than 200,000 people. And it happened again in 2011 at Christchurch, New Zealand, with an earthquake on a minor fault no one knew about in advance – but still the earthquake produced the greatest losses in New Zealand’s history.

“The lesson there is that you never know which one is going to nail you,” Yeats said, “but it pays to be prepared.”

New book looks at hotspots around the world for mega-quakes

This is a high school running track in Taiwan crossed by the Chelungpu fault in an earthquake in September 1999. -  Bob Yeats, Oregon State University.
This is a high school running track in Taiwan crossed by the Chelungpu fault in an earthquake in September 1999. – Bob Yeats, Oregon State University.

At the beginning of 2010, Oregon State University geologist Bob Yeats told a national reporter that Port au Prince, Haiti, was a “time bomb” for a devastating earthquake because of its crowded, poorly constructed buildings and its proximity to the Enriquillo Fault.

One week later, a magnitude 7 earthquake destroyed Port au Prince, killing hundreds of thousands of people and devastating the economy of Haiti.

The clock is ticking on many other earthquake faults throughout the world, Yeats says, and though he did not “predict” the Haiti earthquake, he can point to other places that could face the same fate. He outlines some of these areas in a new book called “Active Faults of the World,” published by Cambridge University Press.

“We are not yet to the point where we can predict earthquakes,” said Yeats, a professor emeritus in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “What we can do is tell you where some of the most dangerous faults lie – and where those coincide with crowded cities, few building codes, and a lack of social services, you have a time bomb.

“Unfortunately, we can’t say if an earthquake will strike today, tomorrow or in a hundred years,” he added. “But in all of these locations it will happen someday – and unless something is done to improve conditions, many thousands of people will die.”

In his book, Yeats notes that the greatest migration in human history is of people moving from rural areas to “megacities” in the developing world. People have flocked to these mega-cities where multi-level housing and businesses are rapidly built, and often poorly constructed and poorly inspected. When many of these locations last had a major earthquake, their population was small and a majority of the people was living in one-story dwellings, limiting the loss of life.

Yeats cites as an example Caracas, Venezuela, which has an earthquake plate-boundary fault north of the city. In 1812, a major quake shook Caracas and other Venezuelan cities and killed an estimated 10,000 people – about 10 percent of the population at that time. Today, the population of Caracas is nearly 3 million, but government decision-makers are “not placing earthquake hazards high on their list of priorities,” Yeats said, despite the presence of knowledgeable local experts.

Another city near the top of Yeats’ list of earthquake dangers is Kabul, Afghanistan, which suffered an enormous earthquake in 1505. Because of recent wars, the buildings in Kabul are in poor shape – either poorly constructed, or damaged from bombs. On a visit to Kabul in 2002, Yeats found many families living in the ruins of these buildings.


“If Kabul has a repeat of the 1505 earthquake,” Yeats said, “it could kill more people than have died in all of Afghanistan’s wars in the last 40 years because of the influx of refugees living in crowded, substandard conditions.”

Tehran, Iran, is another heavily populated city situated near a major fault line. Located at the base of the Alborz mountain range, Tehran has some 11 million people in its urban boundaries, and Yeats said they are vulnerable because of poorly constructed housing in many parts of the city – a result of corruption in building construction and building inspection industries.

Other over-populated cities near fault lines with poor building codes on Yeats’ list include Istanbul, Turkey, now under an earthquake hazard warning after a quake of magnitude 7.4 in 1999; Nairobi, Kenya, close to a 7.3 quake in the 1920s; and Guantánamo, Cuba.

“Guantánamo is a bit like Haiti,” Yeats pointed out. “They have a fault just offshore, and yet they have no clue they are at risk because Cuba has not had any catastrophic earthquakes in its 500-year history. The military prison operated by the United States would also be at risk, but as far as I know, the Americans are not contributing their expertise to help Guantånamo prepare for its future earthquake.”

There are many places around the world likely to experience a major earthquake in the future, Yeats says, but the “risk” to human lives may not be as high because of less crowding and better building codes. He points to the 2011 super-quake in Japan, which reached a magnitude of 9.0, yet did not cause nearly as much destruction as the tsunami it triggered.

“The Japanese,” Yeats said, “lead the world in taking earthquake risk seriously.”

Yeats was one of the first geologists to point to the Pacific Northwest as being at risk for a major earthquake, because of its proximity to the Cascadia Subduction Zone. Since he and other OSU scientists first raised awareness of that risk in the 1980s, there has been gradual acceptance that an earthquake will strike in the future.

“But will this acceptance lead to concrete action, such as approving a bond issue for seismic upgrades to old school buildings?” Yeats said. “Will it lead to strengthening communities on the West Coast against tsunamis?”

The OSU professor emeritus hopes his book leads to more awareness of the hundreds of faults around the world – some well-known, and some not. This is the first time someone has attempted to summarize the totality of earthquake faults, and Yeats used his own research and observations, as well as exhaustive literature reviews.

“Knowing about the faults is the first step,” Yeats said, “but preparing for the risk is what really needs to happen. It is kind of interesting that Japan has done a lot of work preparing for an earthquake in their Home Islands, and then one bigger than they expected hits northern Japan, accompanied by a devastating tsunami, whose effects have been felt as far away as Oregon.”

A similar thing happened northeast of Beijing, China, in 1976, when a magnitude 7.8 earthquake struck along a fault line that was not thought to be a major threat, killing more than 200,000 people. And it happened again in 2011 at Christchurch, New Zealand, with an earthquake on a minor fault no one knew about in advance – but still the earthquake produced the greatest losses in New Zealand’s history.

“The lesson there is that you never know which one is going to nail you,” Yeats said, “but it pays to be prepared.”