Angkor Wat much bigger than beleived

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NASA Headquarters, Washington, DC

Jet Propulsion Laboratory, Pasadena, CA

Februari 12, 1998

 

 

NASA RADAR REVEALS HIDDEN REMAINS AT ANCIENT ANGKOR

New evidence of a prehistoric civilization and remnants of

ancient temples in Angkor, Cambodia, have been discovered

by researchers using highly detailed maps produced with

data from an airborne imaging radar instrument created by NASA.

Experts say the findings, made possible by the Airborne

Synthetic Aperture Radar (AIRSAR) developed by NASA's Jet

Propulsion Laboratory (JPL), Pasadena, CA, may

revolutionize the way archaeologists view the

ancient city's development.

 

Angkor is a vast complex of some 1,000 temples covering

about 100 square miles of northern Cambodia. Little is known

of the prehistoric occupation of this fertile flood plain,

but at its height the city housed an estimated

population of one million people. The famous

temples were built from the eighth to thirteenth

century AD and were accompanied by a massive

hydrological system of reservoirs and canals.

Today, much of the civilization of Angkor is

hidden beneath a dense forest canopy and is

inaccessible due to poor roads, land mines and political instability.

 

"The radar data have enabled us to detect a

distribution of circular 'prehistoric' mounds

and undocumented temples far to the northwest

of Angkor," said Dr. Elizabeth Moore, Head of

the Art and Archaeology Department at the School

of Oriental and African Studies at the University of

London. "The site's topography is highlighted by the

radar, focusing our attention on previously neglected

features, some at the very heart of the city.

 

"The radar maps not only bring into question traditional

concepts of the urban evolution of Angkor, but reveal

evidence of temples and earlier civilization either

absent or incorrect on modern topographic maps and

in early twentieth century archaeological reports," she said.

 

"The radar images make apparent many features that

are not readily identifiable on the ground," said

Dr. Anthony Freeman, a radar scientist at JPL who

has collaborated with Moore for the past three

years studying the use of radar on the Angkor site.

"We can see differences in vegetation structure and

some features that are obscured by vegetation cover."

 

In December 1997, Moore surveyed a small mound on the

perimeter of the famous 12th century AD temple,

Angkor Wat, that Freeman had first noticed in the

radar image. "Previous archaeological accounts

from 1904 and 1911 note only two temples and make

no mention of the distinct circular form of the mound.

We found four to six temple remains,

including pre-Angkorean structures," Moore said.

"This suggests occupation of the 12th century site

some 300 years earlier, radically changing accepted

chronologies of Angkor."

 

Angkor's beauty is seen in its temples,

but the greatness of the Khmer city lies in

the multitude of water-related constructions,

according to Moore. The Khmer kings nominally

dedicated temples to Hindu and Buddhist deities,

but the underlying significance was veneration

of ancestral spirits, ensuring fertility of the

land. Management of water was essential,

both for control during the monsoon rains

and conservation during the dry season and

involved the construction of moats, dikes,

canals, tanks, and reservoirs. The largest

of these reservoirs, dated to the 12th century AD,

is five miles long and its function remains a

matter of archaeological debate.

 

"These new detailed topographic maps

have shown us many more hydrological features

and highlighted how they

function in the rituals and daily life of the

Khmer people," Moore explained.

 

 

"Using a technique known as radar interferometry,

which combines two images to create a three-dimensional

topographic map, we can construct a map of the area

surrounding Angkor that is more accurate than most maps

we have of the United States," said Dr. Scott Hensley,

a radar engineer at JPL. "This map lets us see both

natural and human-made water management features at

the site with great clarity."

 

"Angkor is situated on the edge of the Tonle Sap lake,

a unique body of water that doubles in size during the

rainy season. These maps give us new insights into the

human impact on this ecosystem, from the ancient Khmer

to the present day, and are of importance in the study

of our changing Earth," Freeman continued.

 

The Angkor radar images were taken in late 1996 as part

of the AIRSAR Pacific Rim Deployment and were a

follow-up to the 1994 study of Angkor with data

collected by the Spaceborne Imaging Radar-C/X-band

Synthetic Aperture Radar (SIR-C/X-SAR) that flew on

NASA's Space Shuttle Endeavour.

 

Like SIR-C/X-SAR, AIRSAR transmits and receives three radar

frequencies in both horizontal and vertical polarizations.

While both systems use C-band and L-band wavelengths,

AIRSAR has the added benefit of P-band, a longer

wavelength that can penetrate below the forest canopy.

In addition, AIRSAR can be flown in a mode called

TOPSAR that allows it to measure topography and create

three-dimensional images of the surface.

 

AIRSAR images of the Angkor region will be posted

to the Internet at this address:

 

http://www.jpl.nasa.gov/news/

 

AIRSAR flies on a NASA DC-8 aircraft that is

managed at NASA's Dryden Flight Research Center,

Edwards, CA. The AIRSAR instrument is managed by

JPL, a division of the California Institute of Technology,

for NASA's Office of Earth Science, Washington, DC.

This office manages NASA's Earth Science enterprise,

an internationally coordinated effort to study natural and

human- induced changes in the Earth's land, oceans,

atmosphere, ice and life.

 

The AIRSAR flight over Cambodia was funded by

the Government of Thailand. Ground verification

has been made possible by Vann Molyvann, Minister

of State for Culture and Fine Arts, Territorial

Management, Urban Planning and Construction; and

Dr. Ang ChoulŽan of the Cambodian Authority for

the Protection and Management of Angkor and the

Region of Siem Reap.

 

 

Radar shows Cambodia's temple ruins

Previously unknown remains discovered

 

 

Archaeologists using detailed maps produced by a special space radar

instrument have found previously unknown mounds and temple remains at

Angkor.

 

Included in the find are four to six temple remains, including pre-

Angkorean (8th-13th Century) structures hidden beneath vegetation.

 

In December 1996, a Nasa DC-8 jet with specialised radar flew over

and spotted a circular mound at the edge of the moat that to

archaeologists could suggest human settlement.

 

Working with 3-D maps from Nasa, Elizabeth Moore, head of the

department of art and archaeology at London University's School of

Oriental and African Studies, went to the mound to explore it on foot.

 

She found partially exposed remains of a 10th century city at Angkor.

The city was built 200 to 300 years before Angkor Wat, she said. The

finding radically changed her views of an area she had studied for

decades.

 

She said: "The radar data have enabled us to detect a distribution of

circular 'prehistoric' mounds and undocumented temples far to the

northwest of Angkor. The site topography is highlighted by the radar,

focusing our attention on previously neglected features, some at the

very heart of the city."

 

Angkor, a complex of temples covering 259 square kilometers in

northern Cambodia, is virtually uninhabited today. The Angkor Wat

temple dates to 1150. It is surrounded by a moat and approached by a

causeway.

 

Archaeological accounts from 1904 to 1911 noted just two temples in

the area and did not mention the mound. But Moore found ruins of six

temples. The undocumented temples include representations of the

Hindu deities Vishnu and Indra and inscriptions. The mound itself may

date to a few hundred years B.C.

 

Following radar hints, Moore also discovered a site about 26

kilometers away, now a Khmer Rouge camp, with a temple the size of a

football stadium - about half the size of Angkor Wat. But it is not

clear when it was built. Access is limited because the area is under

military control.

 

The Khmer people who settled the region were sophisticated water

managers who created reservoirs, dikes and earthworks, which were

also detected by the Nasa radar.

 

"We've redrawn the map of Angkor in the 10th century and shown that

there were sacred spots in the landscape," Moore said.

 

Archaeologists said the discoveries could profoundly change thinking

about the history of the ancient city, founded in the ninth century

A.D. as the capital of the Khmer empire.

 

In Angkor's heyday, its 1,000 temples spread over 100 square miles.

Angkor Wat has been described as the largest religious monument ever

built.

 

Like many centres of Maya culture in Central America, Angkor was

dominated by temples and had few secular buildings, with most of the

people living at the monuments' edge in dwellings of perishable wood

and thatch.

 

The city was abandoned to the jungle in the early 15th century and

did not inspire archaeological study until the French began

excavations in the 19th century.

 

Radar mapping by aircraft or spacecraft has previously penetrated

desert sands to chart the course of the Nile River in antiquity,

pinpoint a buried "lost city" in Oman and discover centuries-old

ruins along the legendary Silk Road of western China - Agencies