Taxonomy term

extern

Earth's "hum" heard at ocean bottom

Lapping waves or crashing surf may come to mind for most people when they imagine the sounds of the ocean. But the ocean has other voices as well, including one produced by interactions of waves with the seafloor along the continental slope. Unlike waves on the shoreline, this steady, low sound, or “hum,” is inaudible to the human ear and has even proven difficult to detect in recordings made by ocean bottom seismometers (OBS). But in a new study in Geophysical Research Letters, researchers analyzing OBS data have now clearly identified the hum for the first time, which may allow it to be used to develop a better picture of Earth’s interior structure.

04 Apr 2018

LIP split by South Atlantic breakup was sourced from deep

Massive volumes of rock called large igneous provinces (LIPs) have formed many times throughout Earth’s history, fed by some of the planet’s mightiest volcanic events. The volcanic eruptions, sometimes lasting millions of years and pouring hundreds of thousands of cubic kilometers of lava onto the surface, have influenced continental breakups, past climate change and mass extinction events. For everything that’s known about LIPs, however, many questions about them remain, including how far below the surface the erupted magma originate. In a recent study, researchers report that the origins of the Paraná-Etendeka LIP likely lay deep in Earth’s interior.

16 Mar 2018

No river meant no floods for ancient Indus settlements

Large Middle Eastern rivers like the Nile, Tigris, Euphrates and Tiber were critical for the development of early urban societies in Egypt, Mesopotamia and Ancient Rome. And researchers have long thought that the rise, and eventual decline, of cities in the ancient Indus Civilization, which spread across about 1 million square kilometers of what’s now northwestern India and Pakistan from roughly 4,600 to 3,900 years ago, also depended on major rivers, namely those emerging from the Himalayas. But a new study looking at river sediments from the time of the civilization and earlier suggests that wasn’t the case for every ancient Indus city; some may have benefited from being farther away from large rivers and their periodic floods.

23 Jan 2018

Mediterranean drawdown may have caused burst of volcanism

Between 5 million and 6 million years ago, during an event known as the Messinian Salinity Crisis (MSC), large amounts of seawater evaporated from the Mediterranean Sea leaving massive salt deposits in the basin. How much the sea surface dropped during the MSC is debated, but in a new study in Nature Geoscience, researchers suggest that a large, kilometer-scale drawdown of the Mediterranean Sea may explain not just the thick salt deposits but also a pulse of magmatic activity around the region that occurred at the same time as the MSC.

17 Jan 2018

Driftwood reveals ancient Arctic currents and sea-ice levels

Arctic driftwood up to 12,000 years old is giving scientists a better understanding of how ocean currents and sea ice in the far north have changed through the Holocene. In a new study, published in the Journal of Geophysical Research: Oceans, scientists at the University of Oxford in England studied more than 900 pieces of driftwood collected from Arctic shorelines since the 1950s to investigate how shifting Arctic Ocean currents help melt or fortify sea ice.

28 Dec 2017

Opportunist organisms rafted across the Pacific on plastic

Since World War II, fiberglass and plastic — which are stronger, lighter and require less maintenance than wood — have become the materials of choice for coastal infrastructure like docks. An unforeseen consequence of this transition, however, is that when structures built from these durable materials break free from their moorings and drift out to sea, they can serve as resilient rafts for opportunistic organisms. 

21 Nov 2017

Extinct lunar magnetic field lasted longer than previously thought

Magnetized lunar rocks collected by the Apollo missions indicate the moon had its own magnetic field, generated by motion of liquid metal in its core, until at least 3.2 billion years ago. However, what powered the lunar field and how long it lasted has been unclear. Now, new research reveals that the lunar magnetic field lasted until at least 2.5 billion years ago, and possibly even until 1 billion years ago.

17 Nov 2017

Volcanic activity contributed to first of the "Big Five" mass extinctions

During the Ordovician, between about 488 million and 444 million years ago, plant life first emerged on land, while primitive fish and a variety of marine invertebrates flourished in the oceans. Toward the end of the period, however, a mass extinction — the first of the so-called “Big Five” Phanerozoic extinctions — wiped out roughly 60 percent of all marine invertebrate genera. In a recent study, researchers shed new light on a possible cause of the Late Ordovician extinction: volcanic activity.

15 Nov 2017

New method offers improved monitoring of Kilauea

Kilauea Volcano, on Hawaii’s Big Island, has been erupting continuously since 1983, mostly releasing relatively slow-moving lava flows, although rare violent eruptions have occurred. Both explosive and nonexplosive eruptions pose risks to tourists, roughly 2.6 million of whom visit Kilauea annually, as well as to island residents whose safety and property have at times been put in jeopardy by flowing lava.

04 Oct 2017

Less-developed countries with high climate risk need better access to weather and climate data

Rising seas, more persistent droughts and more frequent severe weather events are predicted to occur in the coming decades as the planet continues warming. In a new study, researchers who analyzed spending internationally on weather and climate information services (WCIS) suggest that access to reliable WCIS is becoming more vital for communities and governments looking to assess their vulnerability and to safeguard people and property amid changing climates.

22 Sep 2017

Pages