Uncovering History cave Tsunami in Aceh

A cave discovered near the epicenter triggers tsunami in Indonesia, which contains traces of the giant waves of up to 7,500 years ago. Archive scarce that shows roughly when the next disaster occurs.

These findings suggest a detailed timeline of the longest and tsunamis that have occurred off the coast of the western province of Aceh . Precisely near the center of an earthquake measuring 9.1 on the Richter scale that triggered waves as high as 30 meters on December 26, 2004 , which killed 230,000 people in a number of countries , half in Indonesia .
This limestone cave is located a few meters off the coast of Banda Aceh , one meter above the knee-high waves , and storm and protected from the wind . Only the big waves that can inundate coastal areas capable gushed into .
Among researchers in 2011 and found the sand on the seabed sediment washed into the cave thousands of years ago and ended up neatly in layers between bat droppings like geological cake . Radiocarbon analysis of the above materials were found , including shells and the remains of microscopic organisms , gave evidence of 11 prior to the 2004 tsunami .
Varying periods
The time between the disaster is uncertain , according to the head of the research team Charles Rubin of the Earth Observatory of Singapore ( EOS ) . The last one before 2004 happened about 2,800 years ago , but there are four tsunami that occurred in the period of 500 years before that .
And there may be other natural disasters . Researchers know , for example , that there are two major earthquakes in the surrounding region of Banda Aceh circa 1393 and 1450 . Rubin says a major tsunami could sweep the evidence of other disasters through erosion .
Scientists are still trying to determine the size of the waves that can enter the cave .
" The conclusion that can be drawn is a major disaster that happened in 2004 does not mean it will not happen again in the next 500 years , " said Rubin , adding that the cave was discovered by accident and not part of the planned fieldwork .
completing the Data
The earthquake that led to the 2004 tsunami surprising among researchers because the fault that produced the devastating earthquake , is not active in hundreds of years .
And since the massive earthquake last more than 500 years earlier , there was never any oral history can help understand such risks .
Since 2004, many studies were conducted to try to understand the history of the west coast of Sumatra island to examine a heap of sand , raised coral reefs and GPS data .
" The findings are very significant , " said Katrin Monecke , a professor of earth science at Wellesley College in Massachusetts .
He studied the pile of sand tsunami found in marshes in the area, but was not involved in the study of the cave , which was presented at the American Geophysical Union conference in San Francisco . " Layers of sand in the cave record in a very long period of time and gives information about the frequency of earthquakes . "
Although long -term records are protected in the cave , Rubin said the tsunami frequency remains yet to be known exactly or roughly when disaster can happen in a short period of each other .
Perspective geophysicists
Geologist Kerry Sieh , director of EOS who participated in the study cave , has been able to predict that the giant earthquake rocked Aceh region in the coming decades . They generally come in the form of a cycle and the occurrence of the earthquake in 2004 raised more pressure on the fracture earlier . But its history is very diverse , making it impossible to give precise predictions .
" By studying the type of tsunami that occurred in the past , maybe we can plan mitigation for the next tsunami , " said Ismail Nazli , head of the department of physics and geophysics at Kuala University in Banda Aceh who worked on this project .
The Indonesian archipelago sits on the Pacific Ring of Fire , a series of volcanoes and fault lines surrounding the Pacific Basin . This is where the seismic activity of the largest and most deadly in the world .