News

Lanka’s southern waters hide a gravity anomaly that baffles scientists

Published

2 years ago

2024/11/12

The Earth beneath your feet is far from still. While we understand quite a bit about the Earth’s surface, the interior remains a mystery. (CREDIT: International Centre for Global Earth Models / Wikimedia, CC BY 4.0)

One of the most puzzling phenomena lies beneath the Indian Ocean, south of Sri Lanka, where a massive gravity anomaly known as the Indian Ocean Geoid Low (IOGL) has confounded researchers for decades, said a report published by The Brighter Side News.

It said that this anomaly, marked by a dramatic 106-meter drop in the ocean’s surface, is the lowest geoid anomaly on Earth. Its origin remains a mystery, making it one of the most intriguing unresolved problems in Earth sciences. “The existence of the Indian Ocean Geoid Low is one of the most outstanding problems in Earth Sciences,” says Prof. Attreyee Ghosh, an assistant professor at the Centre for Earth Sciences, Indian Institute of Science, Bangalore.

It said: The ground beneath you may seem stable, but the Earth is in a state of constant motion. While we have a solid understanding of the Earth’s surface, its interior remains largely unexplored. Even with all our technological advancements, we still haven’t developed probes capable of reaching the Earth’s crust, which is just 35 kilometers deep. To uncover the mysteries of the Earth’s core and mantle, we rely on indirect methods.

Though the Earth may look like a perfect blue sphere from space, it’s actually more like a lumpy, misshapen potato. This uneven shape is due to the non-uniform distribution of matter inside the planet, which creates variations in gravity. The movement of tectonic plates, which form mountains and valleys, also contributes to these deformations.

Oceans cover 71% of the Earth’s surface, so these irregularities also affect the shape of the ocean. Without tides and currents, the ocean water would settle into a smooth, wave-like form called a geoid. This geoid rises in areas where gravity is strong and sinks where gravity is weak. These variations in the ocean’s surface, known as “geoid anomalies,” are caused by the distribution of mass deep within the Earth.

One of the most intriguing geoid anomalies is located south of Sri Lanka. Known as the Indian Ocean Geoid Low (IOGL), this massive area is characterized by a significant drop in gravity, causing the ocean surface to dip 106 meters. This “gravity hole” has puzzled scientists for decades.

In a recent study published in Geophysical Research Letters, Prof. Ghosh and her colleagues, along with researchers from the GFZ German Research Centre for Geosciences, investigated the missing mass causing the geoid low.

Past studies attributed it to a remnant of an ancient plate that dived into the mantle beneath another plate millions of years ago, but there had been no convincing explanation until now.

Using numerical models of mantle convection, the researchers explained the mass deficit. Mantle convection involves movement within the Earth’s mantle, where hotter, lighter material rises, and cooler, denser material sinks due to gravity. This movement was driven by seismic tomography models, which use seismic waves to create a 3-dimensional picture of the Earth’s interior.

The researchers discovered that ‘low-density anomalies’—the presence of lighter materials in the upper to mid-mantle beneath the IOGL—caused the gravity low in this region. Mantle plumes, or rising abnormally hot rock, can result in low-density anomalies.

However, no known mantle plume exists beneath the IOGL. Instead, they found hot material rising from the African large low-shear-velocity province (LLSVP) or the African superplume, near the IOGL, which gets deflected eastward and terminates beneath the IOGL. The deflection is possibly due to the fast motion of the Indian plate.

The researchers used supercomputers to simulate how the area could have formed, going as far back as 140 million years. “The Earth is basically a lumpy potato,” said Ghosh. “Technically, it’s not a sphere, but what we call an ellipsoid, because as the planet rotates, the middle part bulges outward.”

To find a potential answer, Ghosh and her colleagues used computer models to set the clock back 140 million years in order to see the big picture, geologically. “We have some information and some confidence about what the Earth looked like back then,” she said. “The continents and the oceans were in very different places, and the density structure was also very different.”

From that starting point, the team ran 19 simulations up to the present day, recreating the shifting of tectonic plates and the behaviour of magma inside the mantle. In six scenarios, a geoid low similar to the one in the Indian Ocean formed. The distinguishing factor in all six models was the presence of plumes of magma around the geoid low, believed to be responsible for the formation of the “gravity hole.”

The plumes themselves originated from the disappearance of an ancient ocean as India’s landmass drifted and eventually collided with Asia tens of millions of years ago. “India was in a very different place 140 million years ago, and there was an ocean between the Indian plate and Asia. India started moving north and as it did, the ocean disappeared, and the gap with Asia closed,” Ghosh explained.

As the oceanic plate went down inside the mantle, it could have spurred the formation of the plumes, bringing low-density material closer to Earth’s surface.

“A geoid low or a negative geoid anomaly would be caused by a mass deficit within the deep mantle. Our study explains this low with hotter, lighter material stretching from a depth of 300 km up to ~900 km in the northern Indian Ocean, most likely stemming from the African superplume,” says Prof. Ghosh.

All News Advertisement

News

INS Airavat makes port call in Colombo

Published

16 hours ago

2026/06/4

Priyan

The Indian Naval Ship (INS) Airavat arrived at the Port of Colombo for Operational Turnaround on 01 Jun 26. The visiting ship was welcomed by the Sri Lanka Navy (SLN) in compliance with time-noured naval traditions.

INS Airavat is a Landing Ship Tank, commanded by Commander IP Patil.

During their stay in the island, the ship’s crew is scheduled to take part in a series of professionally enriching events and camaraderie-building programmes organised by the Sri Lanka Navy.

The Indian naval personnel will also tour several historic and prominent tourist attractions across the country before the ship concludes her deployment.

News

BASL asks govt. to abandon plan to raise retirement ages of CA and SC judges

Published

20 hours ago

2026/06/4

Sahan Weerasooriya

… tells Prez such arbitrary change neither necessary nor desirable

The Bar Association of Sri Lanka (BASL) has urged President Anura Kumara Dissanayake to abandon the controversial plan to increase the retirement age of the judiciary, including the Court of Appeal and the Supreme Court.

In a statement issued by the BASL President Rajeev Amarasuriya and its Secretary Nalin de Silva, the BASL pointed out that the proposed increase of the retirement age of the judiciary would undermine the independence, integrity, dignity, and public confidence in the Judiciary, which is essential for the maintenance of the Rule of Law and democratic governance in Sri Lanka.

The text of the BASL statement: “The Bar Association of Sri Lanka (hereinafter referred to as “BASL”) notes with grave concern reports in the public domain that the Government is considering the introduction of an amendment to the Constitution to increase the age of retirement of Judges of the Court of Appeal and the Supreme Court.

It is the considered view of the BASL that the age of retirement of the judges of the Court of Appeal and the Supreme Court which has stood at 63 years and 65 years respectively from the promulgation of the 1978 Constitution, should not be changed arbitrarily and that such a change is neither necessary nor desirable.

To do so will result in the loss of public confidence in the integrity of the legal system and of the Government’s commitment to preserve and protect the rule of law and the independence of the judiciary. Members of the public are likely to question the motives of the Government in bringing in a Constitutional amendment solely for this purpose.

Your Excellency is no doubt aware that the cadre of the Judges of the Court of Appeal was increased from 12 to 20 Judges (including the President of the Court of Appeal) and that of the Supreme Court from 11 to 17 Judges (including the Chief Justice) by the 20th Amendment to the constitution certified on 29th of October 2020. With such enhancement, workwise, there cannot be a real requirement to extend the retirement ages of these judges.

Your Excellency is aware that altering the retirement age of judges of the apex courts would have to be done through a Constitutional amendment. For many years Sri Lanka’s Constitution has been subject to ad hoc amendments, sometimes in order to cater to the political needs of the government in power and often contrary to the interests of the rule of law, the independence of the judiciary and the judiciary.

Extending the retirement age of the sitting Judges of these Courts at this point of time is likely to be viewed by the public as a blatant attempt to interfere with the judiciary. We believe that to go ahead with such an ad hoc move will also be an affront to the Honourable Judges of those courts.

If the Government goes ahead with such a move it will set a dangerous precedent for future Governments too to introduce ad hoc amendments to the Constitution in respect of the functions of the Judiciary.

The independence of the Judiciary and the public confidence reposed in it, are indispensable pillars of the Rule of Law and the democratic framework of our Republic. In that regard, it is of paramount importance that the Judiciary must not only remain independent in fact, but must also be seen by the public to be wholly independent, impartial, and free from even the slightest perception of influence, favour, accommodation, or impropriety.

The Bar Association of Sri Lanka is therefore constrained, in the discharge of its duty to uphold and safeguard the Rule of Law and the independence of the Judiciary, to respectfully express its serious concern regarding any such proposed amendment, which is neither in the interests of the Judiciary and nor of the people.

In the circumstances, the BASL respectfully urges Your Excellency not to proceed with any proposed constitutional amendment seeking to increase the retirement age of the members of the Judiciary including Judges of the Court of Appeal and the Supreme Court.

We remain confident that Your Excellency will give due consideration to the importance of preserving and protecting the independence, integrity, dignity, and public confidence in the Judiciary, which is essential to the maintenance of the Rule of Law and democratic governance in Sri Lanka.”

Govt. declines to respond

A member of the Cabinet yesterday declined to comment on the BASL’s letter to President Anura Kumara Dissanayake. The Minister said that he wouldn’t comment for the time being.

News

New US tariffs proposed on 60 countries, including Sri Lanka

Published

20 hours ago

2026/06/4

Sahan Weerasooriya

12.5% additional duties on goods imported from Colombo

The US has proposed additional duties of 10% or 12.5% on imports from 60 economies, including Sri Lanka, over their alleged failure to curb trade in ‌goods made with forced labour.

The proposal made by US Trade Representative’s (USTR) office in terms of Section 301 unfair trade practices investigation to be released, news agencies reported, pointing out that the Trump administration was seeking to rebuild its emergency tariffs, which were struck down by a US Supreme Court decision in February.

The USTR said it determined that it would impose 10% duties related to ⁠the forced labour investigation on imports from Canada, Ecuador, the European Union, Indonesia, Mexico, Pakistan, Argentina, Bangladesh, Cambodia, El Salvador, Guatemala, Indonesia, Malaysia, Taiwan and Britain.

The trade agency said it would impose additional duties of 12.5% on the remaining 45 countries that were investigated.

“The failure of our most important trading partners to address the importation of goods made with forced labour is unacceptable,” US Trade Representative Jamieson Greer said in a statement. “This creates a dynamic where American workers are forced to compete globally on an unlevel playing field.”

According to the trade agency, the USTR found that Sri Lanka has failed to impose and effectively enforce a forced labour import prohibition.

The USTR noted that the results of its investigation indicate that the acts, policies and practices of Sri Lanka related to the failure to impose and effectively enforce a forced labour import prohibition are unreasonable and burden or restrict US commerce.

Accordingly, it has proposed to impose 12.5% additional duties on goods imported from Sri Lanka.

The USTR said it also was proposing a textile mechanism that would allow for a certain volume of apparel and textile imports ‌to ⁠enter the US at a reduced tariff rate, though the duties and volumes were not disclosed.

The announcement comes ahead of the July 24 expiration of a 10% temporary tariff imposed by the Trump administration on February 20, the day the Supreme Court struck down US President Donald Trump’s tariffs under the International Emergency Economic Powers Act.

On Monday, the USTR proposed ⁠a 25% duty on many Brazilian goods as a result of a Section 301 investigation into the country’s digital trade practices and preferential tariffs. The trade agency is also expected to soon unveil the findings of another major Section 301 probe into ⁠the buildup of excess industrial capacity in 16 trading partners, including China.

In the forced labour findings, the USTR said it would exempt from the tariffs a number of products, including energy, rare earths and certain ⁠other metals, beef, coffee, certain fruits and vegetables, pharmaceuticals, organic chemicals and aircraft parts.

The USTR said it would accept public comments on the proposed tariffs and other remedies through July 6, with a public hearing scheduled for July 7.