There was a
sharp earthquake near the city of Campobasso
yesterday. Naples is close enough for such a tremor to be
felt. I didn't feel it, but I was out walking around in
the city, where the normal rumblings of passing traffic
might make it difficult to tell. Others, however, tell me
they felt the quake quite perceptibly —or, at least, "saw"
it in the form of chandeliers moving slightly. Those
working high up in the skyscrapers of the new Civic Center
on the eastern side of the city really noticed it,
however. Offices and schools were evacuated successfully.
Italians are more used to*1
the Mercalli scale**2
for measuring quakes. Unlike the Richter scale and recent
Moment Magnitude scale, which measure the magnitude of an
earthquake in terms of actual amount of energy released,
the Mercalli scale is a description of perceived effect on
the environment. The quake yesterday was 5.4 on the MMS
scale and 8 on the Mercalli (MMI, Modified Mercalli Scale).
1.*This comment from July 2019. "...more used to..." That may have been the case years ago. Today, news media generally report that the quake "measured 6 in intensity (or magnitude)" without further comment on what scale they are using. They mean the Moment Magnitude scale. They have been told not to use the term "Richter" anymore but they're not sure why (and probably don't care). Their videos show they damage, so that takes care of the 'perceived environmental effect.' I have never heard in the popular media a discussion of the various scales used to measure earthquakes.
2.**Named for Giuseppe Mercalli (1850-1914, image), a volcanologist and Catholic priest. He worked extensively in the south and was the director of the Vesuvius Geological Observatory at the time of his death. (He also wrote extensively about the ever active eruptions on the Aeolian islands north of Sicily, as of July 2019 still quite active.) The Mercalli scale in use today has been modified a number of times to revise descriptions of environmental effects. This Modified Mercalli intensity scale (MM or MMI) is the result of various revisions in 1931, well after Mercalli's death. It is poorly suited for measuring earthquakes in sparsely populated areas but good for comparing damage done by various tremors, and is useful in earthquake engineering and in extrapolating seismic intensity of historical quakes from accurately reported damage. It ranges from 1 (no damage or visible effect) to 12 (total destruction).
(Image is of a recent Italian postage stamp commemorating Mercalli.)
Some of the descriptive parameters (presented here in no particular order) include :
The only time I have ever truly and solidly felt a quake here was the big one in 1980. There was no doubt about that one. The entire building I was in swayed for many seconds as the intensity built and then gradually faded. The panic in the neighborhood was almost total. The epicenter was many miles away from Naples and there the damage and loss of life was considerable. In the city of Naples, itself, there was little severe damage. Some people were hurt in the panic by, for example, falling as they tried to run downstairs to get out of buildings. My mother-in-law was in a lift and got the scare of her life as the lift shook and banged against the sides of the shaft.
So, people around here are getting a little jumpy. What with Etna erupting for the last few days a few hundred miles to the south on Sicily—and, then, a sharp quake there during the eruption—people around here just stare over at Vesuvius and wonder and wait. They had a practice evacuation about a year ago in the area that would be immediately affected by an eruption of Vesuvius. It went very well: about 500 volunteer subjects were evacuated along designated escape routes. No problems. The difference between such a drill, however, and the real thing cannot be overstated. The area near Mt. Vesuvius is the most populated area in Europe. It is difficult to imagine hundreds of thousands of inhabitants calmly moving along assigned routes to safety.
(Later: 4. 14 p.m.) Even as
I write, there has just been another quake. I felt this
one since I am sitting in my flat on the 4th floor. The
vibrations come up strongly through the building and the
height accentuates the sway. The chandeliers danced around
very nervously, as well. The television broke in with a
bulletin that the epicenter is about in the same place as
the one yesterday, meaning the same long-suffering
villagers are getting hammered again. There are no
immediate reports as to victims, but the television now
reports that, grotesquely, the quake struck during a
memorial service for the children who died in yesterday's
(There is a separate entry about the geology of the Bay of Naples. Click here.Also see: Other Earthquakes)