| Geographical Square Miles. | |
|---|---|
| ward; being that within which the shock could have been easily perceived by instrumental disturbance | Area uncertain. |
Each of these areas, includes those preceding and within it.
Upon the Map C, I have laid down for comparison, the first and second isosesimals, of the great earthquake of 1783, and those of the shock of Melfi of 1851, and the second isoseismal only, of thirteen others, of the greatest earthquakes upon record in Italy, with their dates.
These areas, with the exception of the two first, are only tolerable approximations, the scanty and incomplete accounts admitting of no more. On examining the several curves, it will be seen, that with the exception of that of 1783, this earthquake of December, 1867, has been probably the most formidable and wide-spread, that is known to have desolated Italy; and it is very doubtful, if the excess in the seismic areas, of that of 1783, as laid down from the best accounts, be not considerably exaggerated, for the meizoseismic area of the latter, certainly does not appear, to have passed much beyond, the Calabrian plain, opposite the Gulf of St. Euphemia; and hence this area of greatest effort, was not greatly larger, than that of the shock of 1857.
The only earthquake, whose first isoseismal (blue in the original) compares in area, with those of 1783 and 1857, is that of 1740, in the north, which is said to have extended with damage, from Volterra to Milan. The records of that, however, as well as of the one of 1672, on the Adriatic
