348 



NATURE 



[August 7, 1890 



when it is observed. This applies particularly to the mere 

 fact of the perception of the shock, as a knowledge of 

 the places where it is just not felt is of service in enabling 

 us to determine the boundary of the disturbed area. 



The questions are arranged in the following sections : 

 A, for places where the shock is felt ; B, for those where 

 it is not felt ; and C, inquiries to be made after the shock. 

 In each case, the questions to which it is most important 

 that answers should be given are marked with an asterisk. 



A.— For Places where the Earthquake is felt. 

 I. — Place of Observation. 



* (a) Its name and position. 



(3) Nature and form of the surrounding ground, espe- 

 cially with reference to its geological structure and the 

 neighbourhood of mountains, rivers, cliffs, &c. 



2. — Situatioti of Observer. 



* {a) Whether indoors or in the open air ; if indoors, 

 on which floor of the house. 



{b) If indoors, the direction of the street or of the 

 longer axis of the house (if detached). 



* {c) How occupied at the moment of the shock — 

 lying down, working, &c. 



3. — Time of Occurrence. 



* {a) Time at which the shock was felt ; if possible to 

 a tenth of a minute. 



*{b) Is the time given the correct time obtained after 

 comparison with an accurately rated chronometer ? and, 

 if so, how long after the shock was the comparison made, 

 and how is the chronometer regulated.? 



4. — Nature of Shock. 



* Describe the nature of the shock as closely as 

 possible, stating especially : {a) the number of the more 

 prominent vibrations ; (b) their relative intensity ; {c) 

 whether there was any tremulous motion before or after 

 the vibrations ; {d) whether any vertical motion was 

 perceptible ; [(^) whether, in the latter case, the move- 

 ment in the principal vibration was first upwards and 

 then downwards, or vice versa]. 



5. — Duration of Shock. 



* Total duration, exclusive of that of the sound phe- 

 nomena (stating whether estimated, or determined by 

 watch). 



6. — Intensity of Shock. 



* Was the shock strong enough (a) to make win- 

 dows, doors, fire-irons, or crockery, &c., rattle ; {b) to 

 cause the chair or bed on which you were resting to be 

 perceptibly raised or moved ; [c] to make chandeliers, 

 pictures, &c., swing, or to stop clocks ; (d) to overthrow 

 ornaments, vases, &c., or cause plaster to fall from the 

 ceiling ; {e) to throw down chimneys or make cracks in 

 the walls of buildings 1 



7. — Direction of Shock. 



{a) Direction of the principal shock or shocks. 



{b) Means by which the direction was ascertained. 



{c) Was any change of direction perceptible during the 

 earthquake ? 



8. — Sound-Phenomena. 



*{a) If any rumbling sound was heard at the time of 

 the shock, what did it resemble ? 



[* {b) Did the sound end abruptly, or die away 

 gradually ? 



* {c) Did the sound become deeper or higher towards 

 the end .?] 



* {d) Did it precede, accompany, or follow the shock ? 

 (Times useful, especially the intervals between the be- 

 ginning of the shock and of the sound, and between the 



NO. 1084, VOL. 42] 



ending of the same ; stating whether estimated, oi* 

 determined by a watch.) 



* {e) Duration (given by sa and 8<5, if not determined 

 separately). 



9. — Effect oil the Water of Ponds, &-'C. 



Were any movements observed in the water of ponds, 

 rivers, lakes, or the sea, at, or shortly after, the time of 

 the shock ; if so, of what kind ? 



Accessory Shocks. 



* Were there any slight shocks preceding or following 

 the principal shock or shocks ? If so, a list of these, 

 with the place of observation, time of occurrence, and 

 answers to any of the above questions, would be of great 

 value. 



B.— For Places where the Earthquake is not 

 felt.^ 



I . — Place of Observation. 



* (a) Its name and position. 



* {b) Nature and form of the surrounding ground, 

 especially with reference to its geological structure and 

 the neighbourhood of mountains, rivers, cliffs, &c. 



2. — Situation of Observer. 



* (a) Whether indoors or in the open air ; if indoors, 

 on which floor of the house. 



* (b) How occupied at the moment of the shock — lying 

 down, working, &c. 



C. — Inquiries to be made after the Shock. 



I. — Damage to Buildings. 



{a) Nature of the building damaged. 



ip) Situation to the building, direction of its longer 

 axis ; neighbourhood to the edge of a cliff or bank, and 

 on which side of this it lies ; nature of the rock on which 

 it rests. 



if) If any cracks formed, state in which walls ; the 

 direction and width of the cracks, and the points from 

 which they start (sketches useful). 



{d) If it is noticed that some walls are much damaged, 

 while others at right angles to those are but little affected, 

 what are the directions of these walls ? 



2. — Rotation of Objects. 



* (a) If objects, such as chimneys, grave-stones, gate- 

 pillars, &c., have been rotated on their bases during 

 the shock, describe the initial and final positions of the 

 objects (sketches useful) ; or state the direction and 

 amount of the rotation (looking down on the object from 

 above, is the direction the same as that in which the 

 hands of a watch rotate, or opposite to that direction ?). 



(b) Is there any evidence of rotation in bodies with a 

 circular base .'' 



3. — Effects on the Groiind, Springs, Qr'c. 



(a) Were any fissures or cracks formed in the ground? 

 If so, state their length, width, depth, and direction, the 

 nature of the ground in which they occur, and their rela- 

 tion to neighbouring cliffs, banks, &c. 



(b) Was the height, quantity, or temperature of the 

 water in springs affected by the shock ? 



4. — Observations in Mines. 

 If the earthquake was felt in a mining district, in- 

 quiries should be made as to the nature of the shock and 

 of the sound-phenomena when observed by men in the 

 mines ; the depth of the workings in such cases, &c. 



' [The value of observations under this heading^ would be greatly increased 

 if they are the result of numerous inquiries made in a district.] 



