The 7.8-magnitude earthquake that devastated Nepal at the weekend is a stark reminder that the Earth-moving forces that shape continents are as active today as they were 4.5 billion years ago when our planet was in the throes of being formed.

"We were near the quake's epicentre the day before it happened – and were near the epicentre of a major aftershock the day after," says Curtin University geologist Zheng-Xiang Li, speaking from Lhasa. "We were here to study how the India-Eurasian collision had driven the uplift of the Tibetan Plateau and the rise of the Himalayas."

Our island continent of Australia is set to join Amasia – in that we're shifting by about seven centimetres a year towards Asia. 

Professor Zheng-Xiang Li.

Professor Li was in Nepal to collect evidence in support of his theory that the Earth's seven major continents are in the process of re-forming to ultimately yield one giant supercontinent. "The speculated future supercontinent has been named Amasia, by Canadian scientist Professor Paul Hoffman," he explains.

The shift towards Amasia has become apparent over the past hundred million years or so, Professor Li points out. "It would take at least tens of millions more years – perhaps several hundred million years – before the new supercontinent is fully formed."

The evidence is compelling: GPS measurements show that the Atlantic Ocean is widening by a few centimetres a year. The Pacific Ocean, on the other hand, is narrowing at a similar rate. 

"If this trend continues, within the next one or two hundred million years, the Pacific will have closed up – resulting in a collision between the American and the Eurasian continents," Professor Li notes. "Australia, meanwhile, is set to join Amasia – in that we're slowly but surely shifting by about seven centimetres a year towards Asia."

It's all coming together: An artist's impression of how the new supercontinent is taking shape. Photo: Li and Zhong, 2009

Core

Supercontinents form by gathering most or all continents together. The India-Eurasia collision signifies the addition of India to the core of the future supercontinent, Professor Li says.

"India actually joined Eurasia some 50 million years ago," he explains. "The tectonic force kept driving India to move northward, causing the Indian continent to subduct – or slide – underneath the Himalayas and southern Tibet."

The weekend earthquake occurred at about 20 kilometres beneath the Himalayas. This where the two crustal plates slide against each other and build stresses that lead to countless quakes.

Revolution

Professor Li is working with colleagues abroad to demonstrate that what he calls the "new revolution in plate tectonics" is underway. "By revolution, I mean the theoretical revolution similar to the development of plate tectonics theory in the 1960s," Professor Li explains.

The theory is based on the premise that Earth's outer shell is divided into several brittle sections, called crustal plates, which glide over the mantle, the rocky inner layer above the planet's core. There are seven main plates and numerous smaller ones, all moving and shoving against each other as they slide across the hot mantle. 

"This time, we are about to understand what drives plate tectonics," says Professor Li. His major International Geoscience Programme project, dubbed "Supercontinent Cycles and Global Geodynamics", will investigate the hypothesis that Earth's plates, and its deep mantle, evolve in super-cycles.

The project, sponsored by UNESCO and the International Union for Geological Sciences, involves a multidisciplinary team of hundreds of scientists and research students from around the world. "Our team will address perhaps the most fundamental geoscience question – how Earth works," he explains.