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EARTHQUAKE REPORTS. Symbols, Notation, etc. 1. Character of the earthquake :— d Local shock perceptible at station, its intensity being expressed on the Rossi-Forel scale, thus : RF 1, &c. v Near shock (origin less than 9°, or 1,000 kilometres, distant). r Distant shock (origin from 9° to 45°, or 1,000 to 5,000 kilometres, distant). u Very distant shook or teleseism (origin more than 45°, or 5,000 kilometres, distant). 2. Phases of the seismogram [each of the following symbols may denote — (a) the phase itself ; or (6) the time of arrival of the first waves of that phase at the station ; or (c) the time of transit of those waves from the origin in seconds. There will be no ambiguity]. P .. .. .. .. Longitudinal waves, direct (first phase or first preliminary tremors). PR (or PR,), PRjj .... PR, .. Longitudinal waves, reflected once, twice, n times at the earth's surface. S .. .. .. .. Transverse waves, direct (second phase or second preliminary tremors). SR (or SRi), SRa .... St' rl .. Transverse waves, reflected once, twice n times at the earth's surface. S —P .. .. .. Interval (in seconds) between the arrival of the P waves and the S waves. PS .. .. .. .. Waves changed from longitudinal to transverse oscillation, or vice versa, through reflection at the earth's surface. L .. .. .. .. Long waves (chief phase or principal part; regular waves). L[, Lo .... L n .. .. Successive series of L waves. L .. .. .. .. Long waves passing along the major arc of the great circle through the epicentrum and the observatory. (Repeats of L or I j after a circuit or circuits of the earth are noted in the " Remarks.") M .. .. .. .. Greatest motion in the chief phase. Mj .. .. .. .. Maximum of the Lj waves. C .. .. .. .. Tail or end portion F .. .. .. .. End of discernible movement. 3 Nature of the motion :— or \ ( Beginning of the motion, used either alone or with one of the symbols in e gradual/ " '" t 2 denoting phase. T (period) .. .. .. Time of one complete oscillation (to and fro). A .. .. .. .. Amplitude of the motion, measured from the median line, in millimetres (mm., as shown on the seismogram), or in mikrons (p, actual movement of the ground) : (/j. = 1/1000 mm.). A e .. .. .. .. E-W component of A. A n .. .. .. .. N--S component of A. A v .. .. .. .. Vertical component of A. 4 General: — Time .. . . .. G.C.M.T., Greenwich civil mean time, Oh. or 24h. = midnight. E (epicentrum) .. .. Position of epicentre. 0 (origin) .. .. .. Time of shock at origin. <p ■ ■ .. .. .. Latitude. X .. .. .. .. Longitude from Greenwich. A .. .. .. .. Distance from epicentre in degrees (°) or in kilometres (kms.). 5. The Observatory:—■ C lat *-! 43° 31' 48" {a ) Its position (latitude and longitude): 172° 37' 13" (llh. 30m. 28-95.). Its height (in metros and in feet) above mean sea-level: Bm. (25 ft.). (b.) The kind of seismograph : Milne seismograph No. 16. How installed (E.-W., N.-S., or vertical) : Boom N.-S. Natural period (in seconds): 16 +. Magnification : 6. Damping : Nil.

Earthquake Reports.

Time is Greenwich civil moan time ; it is given in hours, minutes, and sei ionds. Oh. or 24h. = midnight. No. Time Date. Character. Phase. G.C.M.T. i Amplitude. Boom I Period. Ac. Itemarks. 1 1922. H. M. s. Jan., 1 r S? 19 59 00 L 20 02 18 M 20 05 00 3 r P 8 04 24 S? 8 07 12 • L 8 08 24 M 8 10 42 19 u PR t ? 22 09 24 S? 22 14 00 SR t 22 17 42 L 22 21 24 M 22 32 36 „ 22 r S? 3 33 54 SR t 3 36 12 L 3 39 48 M 3 45 42 22 r SJ 20 56 24 SRj 20 58 36 L 21 00 24 M, 2] 03 48 M 2 21 05 12 31 « l>? 13 42 12 13 44 42 13 50 12 13 52 54 L 14 04 00 M 14 17 36 S. MM. 15 2 10-0 Duration. lh.+. 1-2 Duration, 25m. 19 10-5 Duration, 2h. 22 5 22 .'. 4-2 Duration, 2h. (i 31 u Duration, 2h.+ . 15 5-5