CIS WR. C. DAVISON ON THE INVEENESS 



36. On the Inverness Earthquakes of November 15 to Decemuer 14, 

 1890. By Charles Davison, Esq., M.A. (Eead June 24, 1891.) 



[Communicated by Prof. C. Lapwortii, LL.D., F.R.S., F.aS.] 



Contents. 



Page 



I. Introduction 618 



II. Principal Shock (A) on ]Nov. lo 619 



1. Disturbed Area. 



2. Nature of the Shock. 



3. Intensity. 



4. Sound-phenomena. 



5. Time-relations of the Shock and Sound. 



III. Accessory Shocks 624 



IV. Principal Shock (K) on Dec. 14 626 



1. Disturbed Area. 



2. Is^ature of the Shock. 



3. Intensity. 



4. Sound-phenomena. 



y. Doubtful Shocks 627 



VI. Origin of the Earthquakes 628 



1. Principal Shock of Nov. 15. 



2. Subsequent Shocks. 



3. Conclusion. 



VII. Authorities 631 



I. Introduction. 



The earthquakes felt towards the close of last year in the district 

 round Inverness form an interesting chapter in the recent physical 

 history of Great Britain. Eortunately, the first undoubted shock 

 was the most severe one, and this di'ew the attention of numerous 

 observers to the slighter, but not less important, earthquakes which 

 succeeded it. In some respects the evidence is incomplete, owing 

 to the earl)' hour at which many of the shocks occurred ; but it is 

 on the whole full enough to indicate in outline the succession of 

 events and their relation to the geological structure of the district. 



In studying these earthquakes the accounts given in the local 

 newspapers have been found of some service, but I have chiefly 

 relied on records sent to me in reply to a series of questions which 

 were circulated as widely as possible throughout and near the dis- 

 turbed area. At the end of this paper I have acknowledged in de- 

 tail the help thus received ; but I wish here to offer my hearty 

 thanks to those who have assisted me — first, for the valuable infor- 

 mation which they have placed at my disposal, without which this 

 paper could not have been attempted, but not less for the unfailing 

 courtesy and kindness with which my enquiries have been re- 

 ceived. 



During the period mentioned at least eleven undoubted shocks 

 were felt. Besides these, there were nine others, each depending 

 on the evidence of one witness only, but they were noticed and 



