Now its more or less official--the strong Nov. 9 earthquake felt through a large area of the United States--was centered in Hamilton County just northwest of Broughton.
That's the word of the Illinois State Geological Survey which has just published a 6-page booklet entitled "Notes on the Earthquake of Nov. 9, 1968 in Southern Illinois."
Findings gathered by Survey shows the earthquake was most intense in the Hamilton County area roughly bounded by the village of Dale, Walpole, and Braden. The origin was 12 miles below the surface and the resulting shock, registering a magnitude of 5.
5 on the Richter scale, was felt in some 19 states from Nebraska to North Carolina, Michigan to the Gulf of Mexico.
The Survey said that bricks were thrown or loosened from approximately 40 per cent of chimneys in the Dale-Walpole-Braden vicinity. "Incidences of rotated or fallen tombstones in the area indicate high intensity, it said.
Damage estimated at $5,000 to $8,000 was reported at the Johnson home, a large two-story brick house 2 1/2 miles west of Dale. It included cracked interior walls, fallen plaster and broken chimneys. At Endicott's service station in Dale, sheer cracks
formed in the exterior concrete - block walls," the survey said.
It added that at Braden a television antenna was thrown down and bolts fixing guywires to a roof were pulled out. "Waves four feet high were reported at a pond near town," it said.
Apparently helped by the earthquake was the Clarence Sherman No. 7 Sloan well in seciton 13 of Flannigan township where production increased form 25 barrels to 40 barrels of oil per day. Damage was cited at other oil well sites in Hamilton County north
of Dale and north of Walpole near Tuckers Corner.
Among the other earthquake oddities cited was the fact that a crew working in the eastern part of the Old Ben 24 mine near Loagan in Franklin County reported feeling intense earth movements.
Another crew in the same mine, western portion, on the opposite side of a north-south fault zone, felt no movement.
An old, plugged gas well, 10-60 feet deep in Bond county suffered cracks and shortly after the quake, water spouted from it like a geyser, at first every 15 minutes, but lately with decreasing frequency.
Despite this shacking which left many area people terrified, the area should call itself lucky, earthquake speaking. In this area, the release of energy occurs as numerous small shocks, so small that they cause little overall damage to man-made structu
res, the reports said.
The report gave a comparision if the Nov. 9 earthquake and two other well-known quakes, the New Madrid disturbances of 1811 and the 1964 Alaskan quake, both of which were 8.5 magnitude on the Richter scale. Although the Nov. 9 scale reading of 5.5 may
seem high, the report points out that the energy released in it was about one ten millionth of the energy released by each of the New Madrid and Alaskan earthquakes.