Seismology in Japan | Nature

ABSTRACT _The Earthquake of February 22_, 1880.—The earthquake which occurred shortly after midnight on the morning of February 22 was the most severe since the opening of this country to

foreigners. I have been so much in the habit of noting my watch during the frequent earthquake manifestations by day and night, that I am sure I must have been instantly awakened. My house

was swaying to and fro, windows were rattling, timbers creaking, mortar falling, and pictures swinging violently. Although, as usual on such occasions, I was studying my watch by a night

light, I meditated escape. After forty seconds the motion apparently subsided. There had been two distinct periods of maximum intensity. Taking my lamp, I tried to reach the door, but the

motion was still so great that I had to stop, supporting myself against the wall. When I went down stairs to look at two long pendulums of 20 and 30 feet length respectively, I found them

swinging in arcs of about 2 feet, having broken all the apparatus on the table over which they hung. Hitherto the pointers placed on heavy weights suspended by long wires have been regarded

by me as motionless points during an earthquake, and I have been able to use them accurately oa this assumption even for a shock which Palmieri's instrument indicates as 21°, a shock

which knocked down several chimneys. It would seem that in the last earthquake the house, instead of, so to speak, “eating up” the vibrations, was forced into vibration itself. The period of

this vibration was roughly noted by my neighbour, Mr. Thomas Gray, as nearly one second. At the lower end of one of these pendulums I have small pointers which scratch two smoked glass

plates. These plates are caused to move away during an earthquake, so that relative vibrations are shown in two wavy lines. The direction of the first mark upon the plate tells the direction

of the shock, and also the distance moved by the earth relatively to the steady pointer. The amplitude of the waves tells approximately what the movement has been during succeeding

vibrations. From the number of waves upon a given length of glass we get the rate of vibration, and hence, knowing the velocity of transit, the true wave-length of the earthquake may be

determined. As an example I may mention that an earthquake (December 3, 1879) registered by Palmieri's instrument as 18°, was recorded on 7 inches of one of my glass plates in a curve

of seven very small waves, the amplitude of each of which was about 1 mm. Each wave was formed in half-a-second. The important deductions which may be drawn from even only one observation of

this kind are obvious. The other pendulum I have used only for finding the greatest horizontal movement of an earth particle and its direction. Two pointers push against the motionless

pendulum-bob when an earthquake occurs, and so they are moved in the stand which carries them, deflecting two suspended galvanometer mirrors, and readings of the amount of deviation of beams

of reflected light are taken, I give some examples of the movement of the head of a pile which was driven deeply into the soft soil upon which Yedo is built:— Access through your

institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS Access through your institution Subscribe to this journal Receive 51 print

issues and online access $199.00 per year only $3.90 per issue Learn more Buy this article * Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to

local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support AUTHOR INFORMATION

AUTHORS AND AFFILIATIONS * Tokei, Yokohama, Japan JOHN MILNE Authors * JOHN MILNE View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS

Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE MILNE, J. _Seismology in Japan_ . _Nature_ 22, 208 (1880). https://doi.org/10.1038/022208a0 Download citation * Issue Date: 01

July 1880 * DOI: https://doi.org/10.1038/022208a0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is

not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative