2. The shape of the orbit in which the particles of water travel changes gradually as the wave progresses, as may be seen in the gradually changing form of the waves as-they travel outwards, but the change is slow and, for any given spot, the tracks in which all the particles of water move may be iegarded as similar, and the nature of the wave motion can be defined by the shape of the track follow [...] The movement is in fact just like that of the bob of a pendulum, assuming the direction of travel of the wave to be that of the swing of the pendulum. [...] Returning to the diagram fig ii, the distance from o to 4 is the amplitude of the wave, or the extreme distance which the wave-particle reaches from its normal position ; 4 to 12 is the double amplitude or range of motion of the particle, and the time taken by the wave-particle in travelling from o out to 4 And back through 12 to o is the period of the wave. [...] Whatever may be the nature of the laws which govern the movement of the wave-particle in these surface undulations it is hardly possible that they can be the same in the case of waves which differ so much in size and rate of move- ment as the two forms of surface wave referred to in the preceding paragraph This conclusion appears to be supported by the absence of any passage from the one to the ot [...] In the case of earthquake waves in the region where the shock is severe enough to be felt, nothing of the sort has been recognised and nothing of the sort is to be expected, seeing how heterogeneous are the materials of which the outer crust of the earth is composed.
- Pages
- 481
- Published in
- India
- SARF Document ID
- sarf.100011
Segment | Pages | Author | Actions |
---|---|---|---|
Frontmatter
|
i-vi | R.D. Oldham | view |
Preface
|
i-xxx | R.D. Oldham | view |
Chapter I.—Introductory
|
i-4 | R.D. Oldham | view |
Chapter II.—Narrative Accounts of the Nature of the Shock
|
4-41 | R.D. Oldham | view |
Chapter III.—The Isoseismic Lines and Area Over which the Shock was Felt
|
42-52 | R.D. Oldham | view |
Chapter IV.—The Rate of Propagation and Time of the Commencement of the Shock
|
53-77 | R.D. Oldham | view |
Chapter V.—The Rate and Range of Motion of the Wave Particle
|
78-85 | R.D. Oldham | view |
Chapter VI.—Earth Fissures Sand Vents and Allied Phenomena
|
85-111 | R.D. Oldham | view |
Chapter VII.—The Landslips
|
111-123 | R.D. Oldham | view |
Chapter VIII.—The Aftershocks
|
124-128 | R.D. Oldham | view |
Chapter IX.—Results of an Exploration of the Epicentral Tract
|
129-163 | R.D. Oldham | view |
Chapter X.—The Position and Extent of the Seismic Focus
|
164-179 | R.D. Oldham | view |
Chapter XI.—The Records of the Bombay Magnetic Observatory
|
180-189 | R.D. Oldham | view |
Chapter XII.—Electric Effects
|
189-191 | R.D. Oldham | view |
Chapter XIII.—The Earthquake Sounds with Some Remarks on the Barisal Guns
|
191-207 | R.D. Oldham | view |
Chapter XIV.—The Rotation of Pillars and Monuments
|
207-226 | R.D. Oldham | view |
Chapter XV.—The Unfelt Earthquake
|
227-256 | R.D. Oldham | view |
Appendices
|
257-379 | R.D. Oldham | view |
Index to Place Names of Indian Localities
|
i-xviii | R.D. Oldham | view |
Backmatter
|
i-xli | R.D. Oldham | view |