r(i) = log10 5
where s = 10°* is a reference intensity in centimeters.
at 8: 55am on december 30, 2010, an earthquake measuring 3.8 on the richter scale occurred near the town of
greentown, indiana (50 miles north of indiana's capital, indianapolis). an earthquake of that magnitude is often felt, but
rarely causes damage.
2
73/
m4r
by comparison, the earthquake that struck san francisco in 1906 measured 8.25 on the richter scale. it was
times as intensive as the recent indiana earthquake.