EARTHQUAKES RECORDED.

Press, Volume LVII, Issue 17296, 7 November 1921, Page 6

EARTHQUAKES RECORDED.

SHARP SHOCKS YESTERDAY. A very strong earthquake shock was felt in Christchurch at 8.45 a.m. yesterday, those people who were indoors at the time experiencing a most uncanny sensation, as the tremors appeared to die away and then recommence. The shock caused windows to rattle and hanging lamps to sway in a manner which showed that the earthquake was of more than usual severity. The observatory seismograph showed that the first shock commenced at Bhrs 46.1min a.m. Strong motion continued for several minutes, and minor movements until at least 8.54 a.m. The maximum amplitude (instrumental) occurred at Bhrs 47.8min, and 'the origin was evidently not very distant. The felt movement was in the eastwest direction. The complete amplitude of boom motion of the Milne seismograph at maximum was very nearly 11 millimetres, and at commencement about 3 millimetres. A second distinct shock occurred at 9hrs 15.9min, persisting for about l.lmin. This also was felt, hut the second shows that its energy was very much less than that of the (first shock. There seems a strong probability of a minute change of level to the eastward, about 14 minutes previous to the first shock, and it would be interesting to know whether any such effect was found on the Wellington seismogram. A further mild shock was felt at 8.45 p.m., of intensity between the two above. Yesterday morning's earthquake shocks were felt at Rangiora, but to a less degree than in the city.