As a section/fragment of a main fault line goes silent, it must indicate one of two things: The “seismic gap” may merely be immobile, as a result, two tectonic plates gently gliding past each other or else the segment might be a source of possible earthquakes, silently creating pressure till a foreseeable seismic release over decades.

MIT and Turkey researchers have bring into being a proof for both types of behavior on different fragments of the North Anatolian Fault which believes to be the most vigorous earthquake zones in the entire world. The fault, alike in scale to California’s San Andreas Fault, elongated for about 745 miles across northern Turkey and into the Aegean Sea.

The 20 years of GPS data have been taken by the researchers along the fault, and resolute that the next biggest earthquake is going to hit some five miles west of Istanbul and will likely to happen along a seismic gap beneath the Sea of Marmara. On the contrary, the western segment of the seismic gap seems to be moving devoid of producing large earthquakes.

Michael Floyd said that, a research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences, “Istanbul is a large city, and many of the buildings are very old and not built to the highest modern standards as compared to southern California. From an earthquake scientist’s perspective, this is a hotspot for potential seismic hazards.”

Floyd says, even though it is quite impractical to locate when such a quake might occur but this one could be powerful on the order of a magnitude 7 temblor, or stronger.

Floyd further says “When people talk about when the next quake will be, what they’re really asking is, ‘When will it be, to within a few hours, so that I can evacuate?’ But earthquakes can’t be predicted that way. Eventually, for people’s safety, we persuade them to be prepared. To be prepared, they need to know what to prepare for and that’s where our work can contribute”.

Floyd and his colleagues have published their seismic analysis in the journal Geophysical Research Letters, together with Semih Ergintav of the Kandilli Observatory and Earthquake Research Institute in Istanbul and MIT research scientist Robert Reilinger.

The major earthquakes have happened along the North Anatolian Fault in a about domino-like fashion, breaking sequentially from east to west in the recent decades. One of the latest earth-quake hit back in 1999 in the city of Izmit, just east of Istanbul. It has been reported that the most recent shock, which lasted less than a minute, killed thousands of people. Many scientists have believed that the Istanbul will be near the epicenter of the next major quake as city sits at the fault’s western end.

The MIT and Turkish researchers used GPS data to gauge the region’s ground movement over the last 20 years. From these findings, they will get the accurate idea where the fault may hit next. The researchers took data along the fault from about 100 GPS locations, including stations where data are gathered constantly and sites where instruments are regularly set up over small markers on the ground, the positions of which can be recorded over time as the Earth slowly shifts. Floyd states that, “By continuously tracking, we can tell which parts of the Earth’s crust are moving relative to other parts, and we can see that this fault has relative motion across it at about the rate at which your fingernail grows”.
The researchers calculated the findings from the ground data that, for the most part, the North Anatolian Fault must move at about 25 millimeters or one inch per year, sliding quietly or slipping in a series of earthquakes.

Because there’s now no other method to follow the Earth’s movement offshore, the researchers’ team also used fault models to estimate the motion off the Turkish coast. They identified a segment of the fault under the Sea of Marmara, west of Istanbul that is essentially stuck, with the “missing” slip gathering at 10 to 15 millimeters per year. 250 years ago, this section named Princes’ Island segment, for a close by tourist destination last experienced an earthquake.

The Princes’ Island segment should have slipped about 8 to 11 feet according to the Floyd and colleagues but it hasn’t. In its place, strain has possibly been structuring all along the segment for the last 250 years. If this could be the potential reason to smash the fault in one cataclysmic earthquake, the Earth might shift by as much as 11 feet within just seconds.

Bohnhoff, who has studied seismic patterns in the region says, “The nucleation point is pretty close to the city center, which makes early warning time pretty short i.e. between two to six seconds. As the international airport is situated in an area where ground motion would be high, it would be hard to get in tragedy troops, and unluckily 90% of buildings in Istanbul do not fulfill building codes, and might not resist the expected earthquake.”

Floyd says, “Earthquakes are not regular or predictable. They are far-off random over the long run, and you can go many lifetimes without experiencing one. But it only takes one to affect many lives. In a location like Istanbul that is known to be subject to large earthquakes, it comes back to the message: Always be prepared.”