A Short Note on the Disturbance of the Magnetical and Meteorological Instruments at the Colaba Observatory during the Earthquake of 12th June 1897

Extract

The four instruments, the traces of which are examined, are the declination, horizontal force, and vertical force magnetographs, and the barograph. The instruments being not seismological, the following discussion of the character of the disturbance, based upon the traces of these instruments, must obviously be regarded as an attempt at explanation, and as an attempt only. Colaba, it appears, was situated well outside the area of perceptible shaking, and the distance of the Observatory from the centre of disturbance, whether suboceanic or otherwise, was sufficiently large to render the disturbance as it reached Colaba very feeble, and yet it was just sufficiently strong to leave some record of its peculiar characteristics. All traces have been enlarged about two and a half times, but the exact time and measurements have been derived from the original traces.