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Planet Earth

Earth begins to “wobble” a few months before a giant earthquake

A new study by an international team of geoscientists shows that a strange turn in the Earth’s movement occurred before two of the largest earthquakes in history — the M8.8 great Maule earthquake in 2010 and the M9 Tohoku-Oki earthquake in 2011, which caused a catastrophic tsunami and the destruction of the Fukushima nuclear power plant.

Researchers hope that these movements, which they call “oscillations,” can warn seismologists in the future and give countries enough time to prepare for the disaster.

The 2011 earthquake in Japan was the strongest in recorded history of the country, which killed more than 15,500 people.

Long before this cataclysm, a strange “wobble” of land was recorded from east to west, and then again to the east,

These movements or vibrations occur when one of the Earth’s tectonic plates slides beneath the other, which gets stuck until it breaks, resulting in an earthquake.

“What happened in Japan was a huge, but very slow wobble – it has never been seen before,” said co-author Michael Bevis, professor of earth sciences at Ohio State University.

“But are all such earthquakes preceded by such oscillations?” We do not know, because we do not have enough data. This is another thing to consider when assessing seismic risk in subduction zones such as Japan, Sumatra, the Andes and Alaska. “

Bevis added that although people standing on the island would not be able to detect or notice the wobble, since the movement is only a few millimeters per month for five to seven months, the movement was evident from data recorded by more than 1,000 GPS stations throughout Japan .

Geologists from Germany, Chile and the United States analyzed these data and found a reversal shift of about 4-8 mm east, then west and again east. The group explained that these movements are markedly different from the steady shifts that are constantly generated by land masses.

“The world is broken into plates that always move in one way or another. The movement is not unusual. It is this style of movement that is unusual,” Bevis said.

The professor noted that this wobble may indicate that a few months before the earthquake, the plate under the Philippine Sea had a “slow glide”, the soft underground effect of two neighboring ocean plates under Japan, which ultimately caused a huge westerly and downward swing. This set in motion the Pacific plate and the plate under Japan, producing powerful seismic waves that pushed the whole country.

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This event caused enormous damage to all of Japan, and also led to the fact that most of the island of Honshu was shifted several meters to the east. It caused a tsunami, which reached more than 40 m, and more than 450,000 people were left homeless. Several nuclear reactors at the Fukushima-Daiichi nuclear power plant have melted. In general, it was the worst nuclear disaster since the time of Chernobyl.

Scientists studying seismic activity and plate tectonics are trying to determine the approximate magnitude of the next powerful earthquake and to predict where and when it can occur. However, lead author Jonathan Bedford, also a researcher at GFZ, explained that GPS systems are needed in some subduction zones around the world to use the results of the study to predict earthquakes.

In 2011, Japan had one of the largest GPS monitoring systems in the world, which provided the country with sufficient data and allowed researchers to analyze fluctuations in the earth’s mass several months before the event.

Chile and Sumatra also suffered from catastrophic earthquakes and tsunamis in 2010 and 2004, respectively, but in those days they had less complex systems.

The group examined similar data from the 2010 Maule earthquake in Chile. The network is not so dense, but a large part of the deforming continental plate can still be traced.

Stations on land are usually slightly removed from the subduction zone, since the continental crust is stretched and shortened. However, by analyzing the time sequences of GNSS signals, the researchers found evidence of oscillation-stations suddenly shifted towards subduction zones and again changed their direction, returning to normal movement.

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Soon after the second turn, the rupture tore, and then powerful earthquakes followed.

The group hopes that by tracking fluctuations, countries at risk will be warned and get more time to prepare for the upcoming disaster, and this requires a sensor network.

“We really need to monitor all major subduction zones as soon as possible using high-density GPS networks.”


Planet Earth

Geneticists have clarified the origin of American slaves

Frame from the movie "Django Unchained" -

It is the largest study of DNA from people living in the Americas. It shows where the slaves came from in the United States and reveals the details of their abuse.

The work includes information on 50 thousand people, of which 30 thousand are of African origin. The article, published in the American Journal of Human Genetics , serves as “evidence that genetics can shed light on history,” said Alondra Nelson, professor of social sciences at the Institute for Advanced Study in Princeton.

The study began with the work of Joanna Mountain, senior director of research at the company 23andMe. Together with the team, she created a genetic database, which included mainly information about the company’s clients, whose grandparents were born in regions where slavery flourished. Dr. Stephen Micheletti, the geneticist at 23andMe who led the study, compared it to data from the Slave Travels digital project, which contains information about the people brought in: information on ports of embarkation and disembarkation, the number of enslaved men, women and children. He also collaborated with historians to learn more about the plight of African regions, such as contemporary Angola and the Democratic Republic of the Congo, in the 17th and 19th centuries.

Scientists have found out: the DNA of the study participants from the United States showed their Nigerian origin. This means that there are far more ships that transported enslaved people directly to America from Nigeria than would be expected based on historical records. 

At first, historians “could not believe how many Nigerian ancestors were there in the United States,” Micheletti said. 

Later, after consulting with experts, the study authors learned that slaves were first sent to the British Caribbean Islands, and only then sold to the Americans.

Percentage of people of African descent in Africa, the Americas, and Europe. Red denotes the descendants of slaves from Senegal and Gambia, blue - from the west coast of Africa, green - from Nigeria, orange - from Congo / © Stephen Micheletti
Percentage of people of African descent in Africa, the Americas, and Europe. Red denotes the descendants of slaves from Senegal and Gambia, blue – from the west coast of Africa, green – from Nigeria, orange – from Congo / © Stephen Micheletti

Experts estimate that more than half of the people were brought into the United States and Latin America from West Africa. The study found that the modern black population is genetically related to six regions, among them Senegal, Gambia, Nigeria and Benin. Moreover, according to historical sources, there were more regions from which slaves were exported.

The work also showed that the brought women made a much greater contribution to the modern gene pool than men, although there were much fewer of them. Scientists have calculated that in the United States there are 1.5 times more descendants of slaves, and in Latin America and the Caribbean – 13-17 times. Moreover, in the United States, European men have influenced the modern gene pool of people of African descent three times more than European women, and 25 times more in the Caribbean.

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Planet Earth

The collapse of humanity is predicted with a 90% probability

A new study by theoretical physicists cites truly horrifying numbers. The results of a great deal of work have shown that if human society continues to move in the same direction, then civilization in the form in which we know it now will come to an “irreversible collapse” in a few decades.

The research findings, published in Scientific Reports, are a model for our future. The work is based on data on current rates of deforestation and other resource use. Scientists say that even the most positive forecasts show a 90% chance of disaster.

Physicists at the Alan Turing Institute and Tarapaki University predict that the last forests on Earth will be cleared somewhere between 100 and 200 years of this century.

Combined with global population changes and resource consumption, this is an incredible blow to humanity. In light of this, scientists say that society as we know it may cease to exist within the next 20 to 40 years. There is good news, the researchers note that from a global perspective, the rate of deforestation has actually slowed in recent years.

However, they are still too large and continue to suffer losses as newly planted trees cannot protect the environment as well as mature forests.

“Calculations show that while maintaining the real rates of population growth and consumption of resources, in particular forest resources, we have several decades left before the irreversible collapse of our civilization,” the article says.

A fundamental transformation will be required to prevent collapse. The authors say that the main driving force behind the collapse right now is that the consumption of planetary resources is not taken seriously because it is driven by the economy.

Our civilization gives preference to the interests of individuals, countries or territories, without caring about the entire ecosystem. Therefore, in order to stop the catastrophe, people need to reconsider the current model of society, and accept the one that puts the interests of the ecosystem above the individual.

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Planet Earth

Overpopulation is canceled. Scientists predict a drop in the number of people on Earth

In the next fifty years, the world’s population will decrease, according to American scientists. Moreover, by the end of the century, more than half of humanity will be very old. These data contradict previous forecasts. 

Overpopulation is near

In the middle of the twentieth century, there were about three billion people on Earth. In 1987 – already five, 1999 – six, in 2011 – seven. Based on these data, the United Nations Population Fund (UNFPA) predicted that by 2100 the world’s population will exceed ten billion, and possibly approach 15 billion if the birth rate increases. 

So far, this indicator has only been declining: in the 1950s, there were six children per woman, in 2011 – about two. When forecasting growth, experts based on the fact that humanity as a whole lives better and longer. Australian scientists, after analyzing the statistics of the WHO and the UN, confirmed this scenario. 

They noted that the number of people would grow steadily even if most countries introduced a one-family-one-child policy.Even a global military conflict will not prevent the growth, in which as many people will die as in the First and Second World Wars combined. By 2100, the population will still increase to ten billion, the authors of the work emphasized.

People at the busy intersection of Shibuya district in Tokyo
People at the busy intersection of Shibuya district in Tokyo

According to American researchers, humanity will step over the ten-billion-dollar milestone even earlier – in 2053. True, a rapid leap will happen at the expense of the third world countries, but in developed countries, the population, on the contrary, will significantly decrease. So, Japan will lose 24.7 million citizens, Europe – 12, Russia – 7.9. The population of Africa will double to 2.5 billion.According to researchers from the University of Adelaide, because of this in the near future, people will face a global shortage of water and food. Overpopulation also threatens severe climate change.


The first more cautious forecasts appeared in 2014. An international team of scientists, based on UN data collected before 2012, came to the conclusion that the world’s population by 2100 is unlikely to exceed 12 billion. Most likely, more than 9.9 billion will not work. The main growth will come from the African continent. True, even there there will be more and more elderly people, and fewer and fewer young and able-bodied ones.Now researchers are talking about a possible decline in the population in the next century.

 According to the recent work of American specialists, the indicators will continue to grow only until 2064, then, due to the massive availability of higher education and contraception, a decline will begin. At the time of peak, the planet will have 9.7 billion people, but by 2100 – already 8.8, that is, only a billion more than today. At the same time, the share of people over 80 years old will increase almost sixfold.

Mom with a child in the Japanese city of Sendai
Mom with a child in the Japanese city of Sendai

Such conclusions are the result of examining data not on fertility, but on the cohort fertility of women. That is, about the average number of children born to mothers who have not reached a certain age, in this case fifty years.In total, the work used information about the inhabitants of 195 countries. 

Based on this, scientists have calculated: by the end of this century, fewer children will be born in 183 states than are necessary for reproduction.The maximum losses will be incurred by Japan, Italy, Spain, Thailand and South Korea – the population there will decrease by half. In Russia – up to 106 million. Even China will be in trouble : by 2100, only 732 million people will remain in the country. Fertility will also fall in Africa. In Niger today, there are seven children per woman, which will drop to 1.8 by the end of the century.

Record holders for population decline according to PRB forecasts
Record holders for population decline according to PRB forecasts

Attract young and educated

If the restrained forecast comes true, then the problems with the lack of drinking water and food, which are inevitable when the planet is overpopulated, will disappear by themselves. At the same time, a high proportion of the elderly population is likely to require a restructuring of the current political and economic systems. 

They will not be able to effectively solve the problems facing a rapidly aging society, the authors of the work warn. Experts call an open migration policy of developed countries one of the possible solutions. 

According to the staff of the International Institute for Applied Systems Analysis, the model adopted in Canada and Sweden , attracting a large number of well-educated and able-bodied migrants, can most effectively deal with such a challenge. This option, for example, will solve the problem of the aging of the European population.

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