Hours after the first quake, the region was hit by an unusually large aftershock.

Like all large earthquakes, the powerful 7.8 magnitude temblor that struck Turkey and Syria on Monday was followed by dozens of aftershocks, secondary quakes that occur when the movement of the first causes changes in stresses underground.One of those aftershocks, which struck about nine hours after the initial quake, was nearly as strong as the first and measured at magnitude 7.5.

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