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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.

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Presidential pardons: Govt. studying Justice Thurairaja’s recommendations – Minister

Published

2 hours ago

2026/10/13

Sahan Weerasooriya

Thurairaja / Harshana

By Shamindra Ferdinando

Justice and National Integration Minister Harshana Nanayakkara said yesterday that the Cabinet was studying a set of recommendations made by a Committee, led by retired Supreme Court judge Sithambarampillai Thurairaja, PC, regarding a systematic, fair and transparent mechanism for granting presidential pardons to convicted prison inmates.

Attorney-at-law Nanayakkara said so when The Island raised the issue in the wake of the ongoing controversy over prison authorities compelling General Secretary of the Bodu Bala Sena (BBS) Ven. Galadodaaththe Gnanasara to wear civilian attire when produced in court.

The Minister declined to elaborate but said the Cabinet of Ministers was yet to reach consensus on the recommendations. The NPP government, on 25 June 2025, appointed Thurairaja’s committee to study the provisions of the Article 34(1) of the Constitution, along with other statutory acts and judicial rulings.

Justice Thurairaja handed over his report to Justice and National Integration Ministry Secretary Ayesha Jinasena, PC.

The other members of the Committee were Deputy Minister of Mass Media Dr. Kaushalya Ariyarathne, Additional Secretary to the Ministry of Justice and National Integration Piyumanthi Peiris, Additional Solicitor General Nerin Pulle, Senior Deputy Inspector General of Police (SDIG) Legal Asanga Karawita, Chairperson of the Bureau of Rehabilitation Professor Wasantha Subasinghe, Specialist Dr. Chiththahari Abayanayake, former Acting Commissioner of Prisons Nishan Dhanasinghe, Acting Commissioner General of Prisons Prasad Hemantha Kumara, Senior Assistant Secretary (Legal) to the Ministry of Justice and National Integration Roshani Hettige, and Senior Assistant Secretary to the Ministry of Justice and National Integration Chandima Welikala.

The government called for guidelines regarding presidential pardon over a year before the Supreme Court rescinded, in September this year, the presidential pardon granted by Maithripala Sirisena to Ven Gnanasara serving a six-term of rigorous imprisonment for contempt of court. That pardon was granted in May 2019, the third controversial release by Sirisena during his presidency.

President Sirisena pardoned an ex-LTTE terrorist and also the Royal Park murderer Don Shramantha Jude Anthony Jayamaha, in 2016 and 2019, respectively. The Supreme Court, in June 2024, annulled the pardon granted to Jayamaha and ordered his arrest though he still remains free having fled overseas no sooner he was granted the pardon.

News

Mahinda and Shiranthi hospitalised

Published

2 hours ago

2026/10/13

Sahan Weerasooriya

Former President Mahinda Rajapaksa was admitted to a private hospital yesterday morning (12).

Meanwhile, former First Lady Shiranthi Rajapaksa, who is currently in remand custody at Welikada Prison, has been admitted to the Cardiology Unit of the National Hospital in Colombo.

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Monks must be allowed to wear robes when produced in court: Mahanayake Theras

Published

2 hours ago

2026/10/13

Sahan Weerasooriya

SJB MPs meeting Most Venerable Tibbotuwawe Sri Sumangala Mahanayake Thera of the Malwathu Chapter

“JVP did not bomb Dalada Maligawa; it seized weapons from security personnel stationed there”

By S. K. Samaranayake

Most Venerable Tibbotuwawe Sri Sumangala Mahanayake Thera of the Malwathu Chapter yesterday said the President has assured that a final decision on new prison regulations would be taken withn two weeks and until then whenever bhikkhus were produced before court, they must be allowed to wear robes. The monk said the Mahanayaka Thera has written to the Commissioner General of Prisons about their decision.

The Mahanayake Thera said so when SJB MPs, led by General Secretary Ranjith Madduma Bandara, paid a courtesy call on him.

During the meeting, the Mahanayake Thera expressed the following views:

“Currently, a massive campaign is underway on social media to insult and disrespect the Maha Sangha. Some individuals carrying out these attacks are not linked to any political party. We expected the government to intervene and completely put an end to this, which is entirely possible. Laws should be introduced to control this. The insults directed at monks must be stopped immediately. We cannot accept these acts, no matter who commits them. We even saw fabricated images circulated on social media depicting the President in robes and monks in lay attire. Such disrespect is completely unacceptable and must be curbed.

“We also know that some individuals currently representing Parliament have past ties to the Sasana. All we ask is for the mudslinging and insults targeting monks to be halted immediately. Certain elements continue to spread falsehoods about the government. Before this administration came to power, they claimed temples were finished, Buddhism was over, and the Perahera wouldn’t take place. But didn’t they just conduct the Kandy Perahera brilliantly?

“Various people are even complaining about the Casket (Karanduwa) of the Dalada Maligawa. In particular, we saw former Diyawadana Nilame Niranjan Wijeratne criticising the matter. Much of what he said was false. During his tenure, the previous casket was coated in lacquer, which nobody talks about. Replacing the old brass casket with a golden casket is a very commendable step what is wrong with that? Just as items from royal eras are retired and modern equivalents are put to use, the older casket has been given due respect and securely housed. There is no issue there. Some people claim the JVP bombed the Maligawa too. Nothing of the sort happened; it was LTTE terrorists who bombed the temple. The JVP merely seized weapons from the security personnel stationed there.”

Meanwhile, speaking during the visit, SJB General Secretary Ranjith Madduma Bandara and other parliamentarians charged that the current administration is laying the groundwork to turn the country into a secular state.

“It is impossible to introduce new laws for monks within two weeks; it takes much longer,” Bandara noted. “The President has the authority to issue an interim directive that any monk presented to court must appear in robes, but he chooses not to do so because he does not want to. Everyone who speaks out against this is targeted and smeared on social media, driven by a network of 2,000 to 3,000 social media operators tied to the government who attack and insult me. Even during the case of Father Mathew Peiris, who committed murder, his clerical cassock was not stripped. Inside the prison religious leaders were respected.

“The public base of this current government is rapidly eroding as a result of their actions, which is why they are attempting to strike at Buddhism to secure minority votes. Any government is constitutionally bound to protect the Buddha Sasana. We will not allow them to destroy Buddhism and turn this country secular; we will defend Buddhism to the very last, and all Sri Lankans must step forward for this cause.”

Following their meeting at the Malwathu Chapter, the delegation proceeded to the Asgiri Mahavihara, where they met the Mahanayake Thera of the Asgiri Chapter, Most Venerable Warakagoda Sri Gnanaratana Mahanayake Thera, and Anunayake Venerable Narampanaye Sri Ananda Thera to brief them on the current situation.

The delegation included SJB Parliamentarians Ranjith Madduma Bandara, Kins Nelson, Sujeewa Senasinghe, A.C. Alahapperuma, Rohana Bandara, Suranga Ratnayake, Rohini Kaviratne, Chandrani Kirielle, alongside prominent figures such as Lakshman Kiriella, Wasantha Yapa Bandara, Ranjith Aluwihare, and Professor Upul Dissanayake.