H.—34.

since the severe shock of 17th June, 1929. Thirty-eight shocks reached or exceeded R.-F. 6 at Takaka, where they were usually more severe than in other parts of the district. During the latter half of the year activity in the South Island showed signs of diminishing, until November, when a fresh outbreak of strong shocks caused some alarm to residents in the Takaka district. A severe earthquake occurred on the east coast of the North Island on 12th February, the centre of the disturbance being near Porangahau, where the shock exceeded R.-F. 8, and considerable damage was done to property. Several after-shocks were experienced, but the disturbance subsided within one month. The following table gives a summary of the earthquakes felt and reported during the year 1930 :—

The above table shows that, out of the 748 shocks during the year, 125 were felt in the North Island, 648 in the South Island, and 25 in both Islands. Intensities were abnormally high throughout the year, although R.-F. 8 was not exceeded. The maximum intensities experienced in each of the years 1921 to 1930 (inclusive) were as follows :—

The following table gives the number of earthquakes in 1930 whose maximum intensities fell in various numbers of the Rossi-Forel scale : —■

The table indicates that intensity 4 was the most frequently observed.

62

Month. Number of Earthquakes reported. Maximum Intensity Locality of Maximum. North South Both Total (R.-P. Scale). Island. Island. Islands. Shocks. January 2 66 1 67 6 Kahurangi Point. February 28 47 4 71 8 Waipawa, Porangahau. March .. 4 45 49 6 Takaka, Murchison. April 7 74 2 79 7 Gisborne. May 2 56 1 57 6 Takaka, Tophouse, Murchison. June 6 60 2 64 6 Takaka. July 10 47 4 53 6 Westport, Murchison. August 16 66 1 81 6 Takaka. September 12 50 1 61 5 Several places in both Islands. October 13 43 2 54 7 Farewell Spit. November 7 50 2 55 8 Takaka. December 18 44 5 57 7 Takaka. Totals 125 648 25 748 8 Waipawa, Porangahau, Takaka.

Maximum Intensity Maximum Intensity (R.-F. Scale). (R.-F. Scale). 1921 8 1926 .. 8 1922 8 1927 .. 8 1923 6 1928 .. 8 1924 7 1929 .. 10 1925 8 1930 .. 8

R.-P. Intensity. Month. Totals. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. January .. .. .. 3 21 21 18 4 .. 67 February .. .. 1 10 26 20 6 7 .. 1 .. .. 71 March .. .. .. 4 13 18 7 7 .. 49 April .. .... 9 26 23 18 2 1 79 May .. .. 1 7 15 16 13 5 57 June .. .. 2 5 3 33 17 4 64 July .. .. 1 2 13 17 16 4 53 August .. .... 10 18 29 20 4 81 September .. .. 5 6 25 16 9 .. .. 61 October .. .... 5 15 22 10 1 1 .54 November .. .... 4 16 18 10 5 1 1 .. .. 55 December .. .. .. 3 23 15 9 3 4 57 Totals... ..".. 10 68 214 248 153 46 7 2 .. .. 748 v. Per cent. .. 1 9 28 33 21 6 1 1