Evidence Of Tsunamis On Indian Ocean Shores Long Before 2004

Kruawun Jankaew led a team of geologists who unearthed evidence that tsunamis have repeatedly washed over a Thai island during the last 2,800 years.

A quarter-million people were killed when a tsunami inundated Indian Ocean coastlines the day after Christmas in 2004. Now scientists have found evidence that the event was not a first-time occurrence.

A team working on Phra Thong, a barrier island along the hard-hit west coast of Thailand, unearthed evidence of at least three previous major tsunamis in the preceding 2,800 years, the most recent from about 550 to 700 years ago. That team, led by Kruawun Jankaew of Chulalongkorn University in Thailand, included Brian Atwater, a University of Washington affiliate professor of Earth and space sciences and a U.S. Geological Survey geologist.

A second team found similar evidence of previous tsunamis during the last 1,200 years in Aceh, a province at the northern tip of the Indonesian island of Sumatra where more than half the deaths from the 2004 tsunami occurred.

Sparse knowledge of the region's tsunami history contributed to the loss of life in 2004, the scientists believe. Few people living along the coasts knew to heed the natural tsunami warnings, such as the strong shaking felt in Aceh and the rapid retreat of ocean water from the shoreline that was observed in Thailand.

But on an island just off the coast of Aceh most people safely fled to higher ground in 2004 because the island's oral history includes information about a devastating tsunami in 1907.

"A region's tsunami history can serve as a long-term warning system," Atwater said.

The research will reinforce the importance of tsunami education as an essential part of early warning, said Jankaew, the lead author.

"Many people in Southeast Asia, especially in Thailand, believe, or would like to believe, that it will never happen again," Jankaew said. "This will be a big step towards mitigating the losses from future tsunami events."

The team found evidence for previous tsunamis by digging pits and auguring holes at more than 150 sites on an island about 75 miles north of Phuket, a Thai tourist resort area ravaged by the 2004 tsunami. That tsunami was generated 300 miles to the west when the seafloor was warped during a magnitude 9.2 earthquake.

At 20 sites in marshes, the researchers found layers of white sand about 4 inches thick alternating with layers of black peaty soil. Witnesses confirmed that the top sand layer, just below the surface, was laid down by the 2004 tsunami, which ran 20 to 30 feet deep across much of the island.

Radiocarbon dating of bark fragments in soil below the second sand layer led the scientists to estimate that the most recent predecessor to the 2004 tsunami probably occurred between A.D. 1300 and 1450. They also noted signs of two earlier tsunamis during the last 2,500 to 2,800 years.

There are no known written records describing an Indian Ocean tsunami between A.D. 1300 and 1450, including the accounts of noted Islamic traveler Ibn Battuta and records of the great Ming Dynasty armadas of China, both of which visited the area at different times during that period. Atwater hopes the new geologic evidence might prompt historians to check other Asian documents from that era.

"This research demonstrates that tsunami geology, both recent and past tsunamis, can help extend the tsunami catalogues far beyond historical records," Jankaew said.

The new findings also carry lessons for the northwest coast of North America, where scientists estimate that many centuries typically elapse between catastrophic tsunamis generated by the Cascadia subduction zone.

"Like Aceh, Cascadia has a history of tsunamis that are both infrequent and catastrophic, and that originate during earthquakes that provide a natural tsunami warning," Atwater said. "This history calls for sustained efforts in tsunami education."

Findings from both teams are published in the Oct. 30 edition of Nature.

Other co-authors of the Thai paper are Yuki Sawai of the Geological Survey of Japan, Montri Choowong and Thasinee Charoentitirat of Chulalongkorn University, Maria Martin of the UW and Amy Prendergast of Geoscience Australia.

The research was funded by the U.S. Agency for International Development, Thailand's Ministry of Natural Resources and Environment, the U.S. National Science Foundation, the Japan Society for the Promotion of Science and the Thailand Research Fund.

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The above post is reprinted from materials provided byUniversity of Washington. Note: Materials may be edited for content and length

Historic Indian sword was masterfully crafted

75-centimeter-long shamsheer
from the late 18th or early
19th century made in India (Wallace Collection, London).

Italian, UK researchers use non-destructive techniques and show the secrets of forging methods.

The master craftsmanship behind Indian swords was highlighted when scientists and conservationists from Italy and the UK joined forces to study a curved single-edged sword called a shamsheer. The study, led by Eliza Barzagli of the Institute for Complex Systems and the University of Florence in Italy, is published in Springer's journal Applied Physics A -- Materials Science & Processing.

The 75-centimeter-long sword from the Wallace Collection in London was made in India in the late eighteenth or early nineteenth century. The design is of Persian origin, from where it spread across Asia and eventually gave rise to a family of similar weapons called scimitars being forged in various Southeast Asian countries.

Two different approaches were used to examine the shamsheer: the classical one (metallography) and a non-destructive technique (neutron diffraction). This allowed the researchers to test the differences and complementarities of the two techniques.

The sword in question first underwent metallographic tests at the laboratories of the Wallace Collection to ascertain its composition. Samples to be viewed under the microscope were collected from already damaged sections of the weapon. The sword was then sent to the ISIS pulsed spallation neutron source at the Rutherford Appleton Laboratory in the UK. Two non-invasive neutron diffraction techniques not damaging to artefacts were used to further shed light on the processes and materials behind its forging.

"Ancient objects are scarce, and the most interesting ones are usually in an excellent state of conservation. Because it is unthinkable to apply techniques with a destructive approach, neutron diffraction techniques provide an ideal solution to characterize archaeological specimens made from metal when we cannot or do not want to sample the object," said Barzagli, explaining why different methods were used.

It was established that the steel used is quite pure. Its high carbon content of at least one percent shows it is made of wootz steel. This type of crucible steel was historically used in India and Central Asia to make high-quality swords and other prestige objects. Its band-like pattern is caused when a mixture of iron and carbon crystalizes into cementite. This forms when craftsmen allow cast pieces of metal (called ingots) to cool down very slowly, before being forged carefully at low temperatures. Barzagli's team reckons that the craftsman of this particular sword allowed the blade to cool in the air, rather than plunging it into a liquid of some sort. Results explaining the item's composition also lead the researchers to presume that the particular sword was probably used in battle.

Craftsmen often enhanced the characteristic "watered silk" pattern of wootz steel by doing micro-etching on the surface. Barzagli explains that through overcleaning some of these original 'watered' surfaces have since been obscured, or removed entirely. "A non-destructive method able to identify which of the shiny surface blades are actually of wootz steel is very welcome from a conservative point of view," she added.

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The above post is reprinted from materials provided bySpringer Science+Business Media. Note: Materials may be edited for content and length.

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Journal Reference:

1. E. Barzagli, F. Grazzi, A. Williams, D. Edge, A. Scherillo, J. Kelleher, M. Zoppi. Characterization of an Indian sword: classic and noninvasive methods of investigation in comparison. Applied Physics A, 2015; DOI:10.1007/s00339-014-8968-0

First Known Human Found in Ethiopia

 

This is a close up view of the mandible just steps from where it was sighted by Chalachew Seyoum, ASU graduate student, who is from Ethiopia

The first known human lived in Ethiopia 2.8 million years ago, according to two remarkable new studies that also reveal the conditions under which the earliest humans evolved.
Prior to this research, which is published in the journal Science, the earliest known member of our genus was dated to around 2.3-2.4 million years ago, so the new remains push back the history of humanity by approximately 400,000 years.
"Prior to 3 million years, humans were relatively ape-like and partially arboreal, partially bipedal," Brian Villmoare, who led the research on the fossil remains, told Discovery News. "They lived in the forest, had small brains, and did not eat meat or use tools."

"After 2 million years," he continued, "humans have large brains, stone tools, and eat meat, so this transitional period is very important in terms of human evolution."
The 2.8-million-year old remains consist of a fossil lower jaw and teeth. They were unearthed at the Ledi-Geraru research area at Afar Regional State, Ethiopia.
Villmoare, a researcher at the University of Nevada Las Vegas, and his colleagues do not name the individual's species, but it likely is the common ancestor of at least two separate human lineages that split at around 2.3 million years ago, with one remaining in Ethiopia and the other going to Tanzania.
Since only a jaw bone with teeth are all that's believed to be left of the first known human, the scientists cannot say much about what this individual's body looked like.
"But," Villmoare quickly added, "there does appear to have been a general reduction in skeletal and dental elements in this jaw, which is consistent with the transition to the Homo adaptive pattern."
As humans likely evolved from the more ape-like Australopithecus, represented by the famous "Lucy" remains, we started to lose features evolved for a past life in trees and to gain characteristics associated more with modern humans, such as shorter arms.
In a separate study led by Erin DiMaggio of Pennsylvania State University, the ecosystem where the first known human was found is described. Clearly, this individual had a lot of company.
"We found a large number of fossils of grazing animals, similar to modern wildebeests and zebras, which show that early Homo lived in an area of grasslands, similar to the modern Serengeti Plains in Tanzania, except that this habitat had rivers and lakes as we have fish, hippos, and crocodiles, as well as antelope that lived near grasses inundated with water," co-author Kaye Reed of the Institute of Human Origins and School of Human Evolution and Social Change, told Discovery News. "There were very few trees, however, except possibly a few near the water sources."
Reed added that she and her colleagues also recovered saber-toothed cats and hyenas, two types of warthogs and a very large baboon that is related to the modern gelada baboon seen today in the Ethiopian highlands.

15-million-year-old mollusk protein found

A team of Carnegie scientists have found "beautifully preserved" 15 million-year-old thin protein sheets in fossil shells from southern Maryland. Their findings are published in the inaugural issue of Geochemical Perspectives Letters.

The team--John Nance, John Armstrong, George Cody, Marilyn Fogel, and Robert Hazen--collected samples from Calvert Cliffs, along the shoreline of the Chesapeake Bay, a popular fossil collecting area. They found fossilized shells of a snail-like mollusk called Ecphora that lived in the mid-Miocene era--between 8 and 18 million years ago.
Ecphora is known for an unusual reddish-brown shell color, making it one of the most distinctive North American mollusks of its era. This coloration is preserved in fossilized remains, unlike the fossilized shells of many other fossilized mollusks from the Calvert Cliffs region, which have turned chalky white over the millions of years since they housed living creatures.
Shells are made from crystalline compounds of calcium carbonate interleaved with an organic matrix of proteins and sugars proteins and sugars. These proteins are called shell-binding proteins by scientists, because they help hold the components of the shell together.They also contain pigments, such as those responsible for the reddish-brown appearance of the Ecphora shell. These pigments can bind to proteins to form a pigment-protein complex.
The fact that the coloration of fossilized Ecphora shells is so well preserved suggested to the research team that shell proteins bound to these pigments in a complex might also be preserved. They were amazed to find that the shells, once dissolved in dilute acid, released intact thin sheets of shell proteins more than a centimeter across. Chemical analysis including spectroscopy and electron microscopy of these sheets revealed that they are indeed shell proteins that were preserved for up to 15 million years.
"These are some of the oldest and best-preserved examples of a protein ever observed in a fossil shell," Hazen said.
Remarkably, the proteins share characteristics with modern mollusk shell proteins. They both produce thin, flexible sheets of residue that's the same color as the original shell after being dissolved in acid. Of the 11 amino acids found in the resulting residue, aspartate and glutamate are prominent, which is typical of modern shell proteins. Further study of these proteins could be used for genetic analysis to trace the evolution of mollusks through the ages, as well as potentially to learn about the ecology of the Chesapeake Bay during the era in which Ecphora thrived.

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The above story is based on materials provided by Carnegie Institution. Note: Materials may be edited for content and length.