How to Recognize an Earthquake
The rumbling and shaking may have stopped 3,000 years ago, but it’s often still possible to determine whether an earthquake caused it. Although the damage depends on many factors—including the magnitude of the quake; the location, materials, construction and design of the affected buildings; and the nature of the underlying rock or soil—there are several telltale signs to look for:
Neat rows of fallen columns
In ancient public buildings, freestanding columns are unsecured at the base and usually support only light roofs. When an earthquake hits, the columns fall in the direction of the ground motion caused by a quake. At Sussita (in Greek, Hippos), on the eastern shore of the Sea of Galilee, marble and granite columns (above) lie in a row beside their bases, which remain standing on the floor of a church that collapsed in an earthquake in 749 C.E.
Collapsed walls
Fire, war and neglect can all harm walls, but earthquakes cause the most damage—leading walls to collapse as a unit. The flattened walls of the storerooms at Masada, overlooking the Dead Sea, are visible in an aerial photo taken prior to Yigael Yadin’s excavation of the site in the 1960s (above, upper photo).
In places, seven stone courses of the originally 11-foot walls were found lying together horizontally.
At Beth-Shean, in the Jordan Valley, the rounded stone arches from a Byzantine arcade lie where they collapsed as a piece during the powerful earthquake of 749 A.D. (above, lower photo).
Slipped keystones
The strength of arches derives from the wedge-shaped keystone, which distributes weight down both sides of the arch. During an earthquake, horizontal ground motion can cause the stones of the arch to separate slightly and the keystone to slip. When the earth moves only slightly, the keystone is caught dangling from the arch (below, lower drawing).
As shown in a hand-tinted lithograph by the 19th-century artist and explorer David Roberts, a massive keystone slipped dramatically in the entrance of a temple at Baalbek, in northeastern Lebanon, built by the second-century C.E. Roman emperor Antoninus Pius (below). Roberts wrote in his journal, “Earthquakes have shaken this extraordinary remnant; but from the magnitude of the blocks which form the lintel, the central one, being wedge-shaped, has slipped only so far as to break away a portion of the blocks on either side, and thus remain suspended.”
Patched walls
Although the collapsed structures at Masada and Beth Shean remained undisturbed for centuries, buildings in Jerusalem are usually repaired quickly after earthquakes or other disasters. The reconstructed walls, made of stone blocks of various sizes, display a patchwork of architectural styles. Built in the first century B.C.E., what may have been a Judeo-Christian synagogue (above) on Mount Zion was repeatedly repaired after damage caused (at least in part) by intermittent earthquakes.
Crushed skeletons
The most definitive proof of earthquakes is also the most gruesome: skeletons found under collapsed walls.
At Dor, on the coast of northern Israel, excavators found the remains of a 30-year-old woman (above) killed by an earthquake in about 1020 B.C.E. With her arms crossed to protect herself, she fell against a low stone partition (perhaps a bench), seen across the top of the photo. Dubbed “Doreen” by the excavators, the skeleton lay among broken pots beneath a collapsed wall.
The tortured position of the body and its location between a garbage dump and a wall clearly indicate this was not a burial. It is also unlikely that conquerors pushed down the wall, thereby destroying pottery and metalwork they could have looted. Further, the debris covering the floors of neighboring rooms rules out the possibility that the collapse of the wall was an isolated, accidental event.
Pattern of regional destruction
Powerful earthquakes have far-reaching effects. In about 1020 B.C.E., an earthquake destroyed sites from Tel Akhziv (in the Galilee) in the north to Tel Masos (west of the Dead Sea) in the south (map, above).