Adrian J. Boas
On Earthquakes, Past and Future
Updated: Mar 21, 2019
Over the last month, a series of mild earthquakes have taken place in Israel, centring on the region of the Sea of Galilee. Damage has been minor, mostly a few cracks in the pavements and walls. One wonders if perhaps a large stone that popped out of the southern part of the Western Wall in Jerusalem and came crashing down on the designated mixed-gender prayer area below, might be related to these tremors. If so, it was the most significant outcome to date of this recent bout. There are no doubt some who will claim that this last occurrence was a divine message, a warning relating to the government's decision to turn over that part of the wall to use by reform Jews, an issue on which I admit to being too poorly informed about to voice an opinion. More to the point, these tremors have resulted in the usual debates on the need for serious measures to strengthen many of the older buildings in the country, debates that invariably result in decisions to carry out half measures that are only casually implemented. Earthquakes are of course among the most unpredictable of occurrences; even for a country where unpredictability is the rule. But the likelihood that we are due for a major one sometime soon is often voiced by the "experts" (by no means do I emphasise the word as a derogatory comment on the profession of seismologists, but rather to what we might term the "earthquake chasers" that pop up like mushrooms after a rain, whenever the window glass tinkles). The fact is that no one can say with certainty that, because we have had our last major earthquake nearly one hundred years ago, and one a century before that, we can expect to have another one very shortly. For all we know the next one might occur in a hundred years from now, or two hundred years. I am not suggesting we should not take measures. Although (in all likelihood) we won’t be around by then, our great or great, great grandchildren might. Should we take a leaf from the Japanese and start building paper houses? I think not, but we certainly can learn from some of the experience of others and make a greater effort, just in case the "experts" are right.
The crusaders were no strangers to earthquakes. The worst on record was the May 1202 quake, which had an estimated magnitude of 7.6 Ms. Damage was widespread, destroying fortresses and cities throughout the Levant and causing a massive loss of life. Perhaps the most remarkable evidence of this quake can be seen in a building that had been destroyed and abandoned two decades earlier. The Templar castle of Vadum Iacob on the upper Jordan River sits directly on a section of a major tectonic fault. In 1202, the eastern half of the castle slid forward over a metre to the north. There is no more dramatic vision of the sheer force involved that an aerial view of the 150 metre long castle with its three metre thick walls torn apart, as if by the hands of a giant.