Posts Tagged ‘news’

ScienceDaily (Nov. 28, 2012) — Archaeologists from the University of Rhode Island, the Israel Antiquities Authority, and the University of Louisville have discovered the remains of a fleet of early-19th century ships and ancient harbor structures from the Hellenistic period (third to first century B.C.) at the city of Akko, one of the major ancient ports of the eastern Mediterranean. The findings shed light on a period of history that is little known and point to how and where additional remains may be found.

The discoveries were presented on November 15 and 17 in Chicago at the annual meeting of the American Schools of Oriental Research by URI assistant professors Bridget Buxton and William Krieger on behalf of the Israel Coast Exploration project.

According to Buxton, three of the four well-preserved shipwrecks found off the coast south of Akko were first detected using a sub-bottom profiler in 2011. Later, storms stripped off several meters of inshore sediments and temporarily revealed the wrecks, as well as an additional large vessel. The wrecks are now reburied.

During the brief time the shipwrecks were exposed, the Israel Antiquities Authority investigated one of them: a 32 meter vessel which still preserved its brass gudgeon (rudder socket) and many small artifacts, such as plates, a candlestick, and even a cooking pot with bones in it. Laboratory analyses completed this summer by the IAA revealed that the ship’s wood came from Turkey. The team believes these ships may have belonged to the Egyptian navy under Admiral Osman Nurredin Bey, whose ships were severely damaged in his attempt to capture Akko in the Egyptian-Ottoman War of 1831. The town eventually fell to Egyptian land forces under Ibrahim Pasha in 1832.

“These ships have occasionally been exposed and buried again by storms since we found them,” Buxton said. “We’re in a race against time to find other ships in the area and learn from them before storms totally dislodge or destroy them.”

Although shipwrecks from the 1800s are not the highest priorities in a region where civilization goes back thousands of years, Buxton is excited by the discovery for what it tells her about where much older ships may be found.

“Like many underwater archaeologists I’m very interested in finding a well-preserved example of an ancient multi-decked warship from the Hellenistic age,” said Buxton. “These ships were incredible pieces of technology, but we don’t know much about their design because no hulls have been found. However, a combination of unusual environmental and historical factors leads us to believe we have a chance of finding the remains of one of these ships off the northern coast of Israel.”

Buxton believes that the ships they are looking for are likely buried in the coastal sediment, which has built up over the centuries through natural processes. However, time is not on their side. “That protective silt is now being stripped away,” she said. “And it’s being stripped away a lot faster than it was originally dumped, by a combination of development, environmental changes, and the effects of the Aswan Dam.” The Nile River has historically deposited large quantities of silt in the area, but the dam has significantly reduced the flow of silt.

The archaeologists found the ships and another early modern vessel within Akko’s modern harbor while testing their equipment in preparation for an ongoing survey out in deeper water. The sub-bottom profiler detects anomalies below the sea floor. “It’s the gift that keeps on giving,” Buxton said. “We found so many targets to explore that we didn’t have time to check all of them, but even just having information about where things are helps Koby (Jacob Sharvit, director of the IAA Maritime Antiquities Unit) know where to look after any big storms.”

One line of buried targets detected off the southern seawall of old Akko is particularly suggestive. Continuing excavations in this area over the summer revealed an alignment between these targets and a newly-discovered slipway and shipshed structure, which continued out under the sea floor 25 meters from the Ottoman city wall. The feature resembles other naval shipsheds found in places such as Athens where they were used to haul up ancient warships. The excavation project was initially undertaken to strengthen the eroding sea wall, but it also revealed Hellenistic masonry, pottery vessels, an ancient mooring stone, and a stone quay 1.3 meters below the modern sea level. The possibility that much more of the Hellenistic port lies well-preserved under the sea floor is exciting for the archaeologists, because it means that shipwrecks from earlier centuries that have so far not been found at Akko may simply be buried deeper down in the sediment.

“We’ve got fragmentary historic records for this area in the Hellenistic period, and now we’ve found a very important feature from the ancient harbor. Ancient shipwrecks are another piece of the puzzle that will help us to rewrite the story of this region at a critical time in Mediterranean history,” she said.

Located on the northern coast of Israel, the UNESCO World Heritage Site of Akko is one of the few cities in the Mediterranean with more than 5,000 years of maritime history. Also known as Acre, Ake and Ptolemais, its port was an important waypoint for the Phoenicians, Romans, Crusaders, Ottomans and other ancient maritime empires. In the Hellenistic period, it was bitterly fought over by the rival empires of Egypt and Syria.

“Understanding the history and archaeology of Akko’s port is crucial to understanding the broader issues of maritime connectivity and the great power struggles that defined the history of the Eastern Mediterranean during the Hellenistic Age,” Buxton said.

Scientists link deep wells to deadly Spain quake

Posted: October 22, 2012 by phaedrap1 in News
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MADRID (AP) — Farmers drilling ever deeper wells over decades to water their crops likely contributed to a deadly earthquake in southern Spain last year, a new study suggests. The findings may add to concerns about the effects of new energy extraction and waste disposal technologies.

Nine people died and nearly 300 were injured when an unusually shallow magnitude-5.1 quake hit the town of Lorca on May 11, 2011. It was the country’s worst quake in more than 50 years, causing millions of euros in damage to a region with an already fragile economy.

Using satellite images, scientists from Canada, Italy and Spain found the quake ruptured a fault running near a basin that had been weakened by 50 years of groundwater extraction in the area.

During this period, the water table dropped by 250 meters (274 yards) as farmers bored ever deeper wells to help produce the fruit, vegetables and meat that are exported from Lorca to the rest of Europe. In other words, the industry that propped up the local economy in southern Spain may have undermined the very ground on which Lorca is built.

The researchers noted that even without the strain caused by water extraction, a quake would likely have occurred at some point.

But the extra stress of pumping vast amounts of water from a nearby aquifer may have been enough to trigger a quake at that particular time and place, said lead researcher Pablo J. Gonzalez of the University of Western Ontario, Canada.

Miguel de las Doblas Lavigne, a geologist with Spain’s National Natural Science Museum who has worked on the same theory but was not involved in the study, said the Lorca quake was in the cards.

“This has been going on for years in the Mediterranean areas, all very famous for their agriculture and plastic greenhouses. They are just sucking all the water out of the aquifers, drying them out,” he told The Associated Press in a telephone interview. “From Lorca to (the regional capital of) Murcia you can find a very depleted water level.”

De las Doblas said it was “no coincidence that all the aftershocks were located on the exact position of maximum depletion.”

“The reason is clearly related to the farming, it’s like a sponge you drain the water from; the weight of the rocks makes the terrain subside and any small variation near a very active fault like the Alhama de Murcia may be the straw that breaks the camel*s back, which is what happened,” he said.

He said excess water extraction was common in Spain.

“Everybody digs their own well, they don’t care about anything,” he said. “I think in Lorca you may find that some 80 percent of wells are illegal.”

Lorca town hall environment chief Melchor Morales said the problem dates back to the 1960s when the region opted to step up its agriculture production and when underground water was considered private property. A 1986 law has reduced the amount of well pumping, he said.

Not everyone agreed with the conclusion of the study, which was published online Sunday in Nature Geoscience.

“There have been earthquakes of similar intensity and similar damage caused in the 17th, 18th and 19th centuries when there was no excess water extraction,” said Jose Martinez Diez, a professor in geodynamics at Madrid’s Complutense University who has also published a paper on the quake.

Still, it isn’t the first time that earthquakes have been blamed on human activity, and scientists say the incident points to the need to investigate more closely how such quakes are triggered and how to prevent them.

The biggest man-made quakes are associated with the construction of large dams, which trap massive amounts of water that put heavy pressure on surrounding rock.

The 1967 Koynanagar earthquake in India, which killed more than 150 people, is one such case, said Marco Bohnhoff, a geologist at the German Research Centre for Geosciences in Potsdam who wasn’t involved in the Lorca study.

Bohnhoff said smaller man-made quakes can also occur when liquid is pumped into the ground.

A pioneering geothermal power project in the Swiss city of Basel was abandoned in 2009 after it caused a series of earthquakes. Nobody was injured, but the tremors caused by injecting cold water into hot rocks to produce steam resulted in millions of Swiss francs (dollars) damage to buildings.

 

FILE - In this May 12, 2011 file photo, a police officer inspects damage caused by an earthquake the previous day in Lorca, Spain, Thursday, May 12, 2011. Farmers drilling ever deeper wells over decades to water their crops likely contributed to a deadly earthquake in southern Spain last year, a new study suggests. The findings may add to concerns about the effects of new energy extraction and waste disposal technologies. (AP Photo/Alberto Saiz, File)

Earlier this year, a report by the National Research Council in the United States found the controversial practice of hydraulic fracturing to extract natural gas was not a huge source of man-made earthquakes. However, the related practice of shooting large amounts of wastewater from “fracking” or other drilling activities into deep underground storage wells has been linked with some small earthquakes.

In an editorial accompanying the Lorca study, geologist Jean-Philippe Avouac of the California Institute of Technology said it was unclear whether human activity merely induces quakes that would have happened anyway at a later date. He noted that the strength of the quake appeared to have been greater than the stress caused by removing the groundwater.

“The earthquake therefore cannot have been caused entirely by water extraction,” wrote Avouac. “Instead, it must have built up over several centuries.”

Still, pumping out the water may have affected how the stress was released, and similar processes such as fracking or injecting carbon dioxide into the ground — an idea that has been suggested to reduce the greenhouse effect — could theoretically do the same, he said.

Once the process is fully understood, “we might dream of one day being able to tame natural faults with geo-engineering,” Avouac said.

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Jordans reported from Istanbul. Ciaran Giles in Madrid and AP Science Writer Alicia Chang in Los Angeles contributed to this report.