At some point in its history, the keystone in the arch of the Byzantine church in the ancient city of Mamshit "slipped." This indicates that for a split second the arch was stretched open, causing the stone to drop: but then, a microsecond later, the arch was pressed back into position, trapping the stone in a slightly different position, as shown here. Only an earthquake is capable of causing such a shift. Hundreds of destruction patterns were identified and measured at Mamshit, indicating that the city underwent a devastating earthquake in the 7th century.
Earthquakes such as those that recently took place in Turkey and Greece demonstrate anew how powerless and insignificant man is in comparison to the forces of nature. This realization, and the attempts to avoid or reduce the damage caused by these forces may lead to regional cooperation in the Middle East. Initial steps in this direction are currently under way thanks to joint research by scientists form the Weizmann Institute, the Ramon Science Center, and the former Soviet Union.
Earthquakes can wipe whole cities off the map and change the course of history. Striking without warning and lasting only seconds, they leave a changed world in their wake. The ability to predict earthquakes could reduce the damage caused but, unfortunately, a reliable method of earthquake prediction has yet to be developed. The only certainty is that "As it once was, so shall it be again." That is to say, where earthquakes have occurred in the past, they may occur in the future. Therefore, accurate information about past earthquakes could help us plan for the future. For example, such information may dictate the need for safety regulations in the building codes of certain areas.
Modern geophysicists possess a fairly efficient database regarding quakes that have taken place since the beginning of the 20th century. However, reliable information about quakes occurring earlier is almost nonexistent. This may change soon, at least in the Negev region.
Prof. Emanuel Mazor of the Weizmann Institute's Environmental Sciences and Energy Research Department and his colleagues from the Ramon Science Center have examined evidence suggesting the occurrence of earthquakes in several ancient cities in the Negev. During the project, Dr. Alexander Becker, a member of the research team, suggested that Dr. Andre Korzhankov of the Kirgistan Seismological Institute be invited to join the team. Dr. Korzhankov often travels to the site of a quake immediately after the event, in order to record the patterns of destruction caused by the quake. The destruction patterns are indicated by the direction in which rocks and other objects fall. These patterns are then combined with the seismic data (the epicenter, its direction and magnitude), enabling calibration of the damage caused by the quake in comparison to its physical attributes.
The Israeli scientists suggested utilizing the information gathered by Dr. Korzhankov in order to "calculate backwards" various historic seismic events. In particular, they wanted to calculate the magnitude and epicenter of the quakes according to the destruction patterns found in these ancient Negev cities.
During the initial phases, the researchers focused on the ancient Nabataean city of Ovdat. They discovered that the city was demolished by earthquakes not once, as previously thought, but twice: during the 4th century, and again in the 7th. Strong quakes took place in the vicinity during the 9th and 18th centuries as well. The research team was surprised to discover that the epicenter of the 7th-century quake was Negev Mountain, rather than the Dead Sea Valley as earlier assumed. (The other quakes had their epicenter in the Valley, which is a part of the Syrian-African Rift.) Further research pinpointed the epicenter with greater accuracy as being in the vicinity of the Nafha region. The fact that one quake had its epicenter at Negev Mountain while three others were in the Dead Sea Valley testifies to a tectonic divergence between the mountain and the valley: The Rift Valley's tectonic pressure is relieved through numerous relatively small earthquakes, whereas the pressure that develops in the Negev Highland tends to be relieved in a single, powerful eruption.
Mazor thinks this information may encourage the Negev's industrial and urban development planners to take into consideration the region's tectonic nature. Says Mazor: "All peoples of this region have a vested interest in uniting to oppose the forces of nature, cooperating in the attempt to reduce as far as possible the destruction and suffering caused by earthquakes."