Radiocarbon analysis uncovers possible traces of hidden earthquakes off Japan's coast

science & techPhys.org

Radiocarbon analysis uncovers possible traces of hidden earthquakes off Japan's coast

from Phys.org

Researchers at the University of Tokyo have used a new type of radiocarbon analysis to study a sediment core taken from the Kumano Sea off the coast of Japan. This has revealed multiple "hidden" traces of previously unknown earthquakes in the Nankai Trough, where the country's next megaquake is expected to occur. Reconstructing a more accurate picture of the past will help predict future geophysical events and prepare for potential disasters. The work is published in Radiocarbon.

explained

The Nankai Trough (南海トラフ, Nankai Torafu; Southern Sea Trough) is a submarine trough located south of the Nankaidō region of Japan's island of Honshu, extending approximately 900 km (559 mi) offshore. The underlying fault, the Nankai megathrust, is the source of the devastating Nankai megathrust earthquakes, while the trough itself is potentially a major source of hydrocarbon fuel, in the form of methane clathrate.

From Wikipedia: Nankai Trough (CC BY-SA 4.0) ↗

so what

Japan faces a high risk of a very large earthquake, so a longer record of past quakes directly improves forecasts. The method also shows that sediments can preserve evidence that land records miss.

Hampi was once one of the world's largest cities, until its Vijayanagara capital was destroyed in 1565

the gist

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.

how it works

The city was built around a fortified core with temples, markets and water structures along the river, supplied by an extensive network of roads and waterworks. When the empire fell, the city was not rebuilt, so its stone monuments were left standing.

so what

Hampi shows how quickly a great city can vanish after a military defeat, and how a ruined capital can remain sacred. Its ruins give historians a view of medieval South Asia that few other sites can match.

fun fact

The name Hampi comes from Pampa, an old name for the Tungabhadra River.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Image: Wikimedia Commons

source: Wikipedia ↗

2 min

politicsshortCNA2:01

False allegations about Singapore’s hand in Indonesia’s markets and a made-up meeting

from CNA

CNA Verify has found close to 400 posts pushing falsehoods tying Singapore to Indonesia’s stock market rout and to a secret meeting that never took place. Together, they drew nearly 12 million views, and some were circulated by accounts that appeared to be working in concert, across multiple social media platforms.

Here’s how the disinformation campaign targeting Singapore was uncovered.

on YouTube: CNA ↗