986
THE NEW ZEALAND GAZETTE.
[No. 29

been from 20 ft. to 80 ft. high. The effects were observable
over almost the whole of the Pacific Ocean; in the Samoan
Island the sea rose from 6 ft. to 8 ft.; in New Zealand and
Australia the oscillations ranged in amplitude from 3 ft. to
20 ft.; and in Japan from 5 ft. to 10 ft.

On 15th June, 1896, a world-shaking submarine earth-
quake occurred in Tuscarora Deep, the trough-like abyss in
the bed of the ocean just eastward of Japan. After the
characteristic withdrawal of the water, the coast was inun-
dated over a length of 300 miles by waves said to reach to
the height of 50 ft. A two-masted schooner was washed
500 yards inland. The destruction of life and property was
very great. The disturbance was not felt by boats some dis-
tance out at sea, and fishermen knew nothing of the disaster
that had occurred until their return to the coast.

The lesson to be impressed upon mariners in the light of
these experiences is that the chances of safety to shipping
are much increased by proceeding to sea, if practicable, im-
mediately after the occurrence of an earthquake; and this
is especially to be enjoined if the water of the harbour is
found to be draining away after the shocks of earthquake
have been felt. In the open ocean seismic sea-waves are not
generally dangerous to vessels, because their very great length
and moderate height gives them a gentle slope, and their
period is very much longer than that of ordinary sea-waves.

By a study of the charts of deep-sea soundings through-
out the world it can be told quite closely what the expected
state of seismic activity of any given region should be, for
wherever there are very deep oceanic troughs situated
adjacent to mountainous ridges, culminating either above or
below the surface of the ocean, disturbances of the crust of
the earth are likely to be prevalent. In these regions the
forces of nature are, in fact, generally engaged in building up
the ridges by forcing under them material pushed from
beneath the undermined floor of the adjacent deepening
trough.

Although the Mediterranean Sea, the Azores, the West
Indies, and the west coast of South America are districts of
seismic activity, it is generally recognised by investigators
that the most active regions of seismic disturbances are
along the Aleutian, Kurile, and Japanese Islands, and in
the East Indies. Major Dutton, U.S. Army, in his book
entitled “Earthquakes in the Light of the New Seismo-
logy,” mentions the tremendous power of the mighty earth-
quakes in the Aleutian region, and also calls attention to
the prevalence of seismic sea-waves following the earth-
quakes. “The profound depths of the ocean just off the
eastern part of the Aleutian chain is one of the great breed-
ing-grounds of world-shakers. A rather small basin in the
ocean-bottom has here a depth of nearly four thousand
fathoms, and the descent to it is by a long and strong gra-
dient.”

In the Bakerian lecture to the Royal Society, 1906, Pro-
fessor Milne treats of great earthquakes, and says that “the
most active district is at present that of the East Indies.”

After great earthquakes in the Aleutian region new is-
lands are frequently raised from the sea, and several new
volcanoes have broken out within historical time. Seismic
sea-waves of the first class frequently follow, the water first
withdrawing from the range of islands toward the trough to
the south and then returning later as a great wave. This
shows that the sea-bottom to the south sinks after the earth-
quakes by which the region is visited. As the islands and,
in fact, the whole mass of submarine mountains are uplifted
by the disturbance and the sea-bottom afterwards sinks, it
seems that lava is expelled from beneath the trough and
pushed under the adjacent range. The bed of the sea then
gives down to fill up the partial cavity from which the mol-
ten rock has been expelled.

Notice to Mariners No. 26 of 1909.

OTAGO HARBOUR ENTRANCE.—PILE BEACONS.

Marine Department,
Wellington, N.Z., 2nd April, 1909.

IT is hereby notified that three single-pile beacons will be
driven during this month along the eastern edge of the
New Channel between Harrington Point and Black Head in
the following positions:—

Northern Pile .. Harrington Point beacon bearing
N. 18° W., 1,700 ft. distant.

Middle Pile .. Harrington Point beacon bearing
N. 10° W., 2,650 ft. distant.

Southern Pile .. Black Head bearing S. 13° W.,
1,900 ft. distant.

The red single-pile beacon, Black Head S. 25° E. 870 ft.,
has been painted black.

It is notified that the old Bend Channel and the waters
inshore of the above piles are closed for navigation.

All vessels and boats are hereby warned not to proceed to
the eastward of these piles, to avoid danger from grounding
or contact with the groins along the Kaik Beach, which are
covered at high water.

Chart, &c., affected: Admiralty Chart No. 2411; “New
Zealand Pilot,” eighth edition, 1908, Chap. viii, pages 253
and 255; “New Zealand Nautical Almanac,” 1909, pages
194 and 304.

J. CARROLL,
For Minister of Marine.

Notice to Mariners No. 27 of 1909.

Marine Department,
Wellington, 1st April, 1909.

THE following Notices to Mariners, received from the
Board of Trade, London, are published for general
information.

J. CARROLL,
For Minister of Marine.

AFRICA.

EAST COAST.—About 1st January, 1909, Cape Inyack
(Inbaca) F.f. white lt. (25° 58½′ S., 32° 59¼′ E.) was to be
altered to show red from S. 52° W. to S. 64° W. over the
Danae Reef. Feb.

KILIMAN (QUILIMANE) RIVER ENTR.—A. F. white lt., elev.
103 ft., R. 12 miles, is exh. from a red pyra. lt.-h. with
white cupola, 78 ft. high, in 18° 53′ S., 36° 54¾′ E., on wrn.
shore of the entr., 5½ miles S. 52° W. from Tangalane Pt.
Lt.-h. “Position approx.” has been charted against this
lt. Tangalane Pt. lt. has been temp. disc. Feb.

ADEN GULF.

ADEN HARBOUR.—A red conical lt.-buoy, exh. a F. red lt.,
is est. in 12° 47½′ N., 44° 59¼′ E., in the harb., with the
N.-wrn. extr. of Flint Isl. S. 17° E. 325 ft., and Courthouse
Flagstaff S. 40° W. Feb.

RED SEA.

BAB EL MANDEB STRAITS.—Instructions for night sig.:

1. Vessels when wishing to sig. at night to Perim Isl. should
   pass through the large strait, and sig. to the lower sig.-
   station (12° 39′ N., 43° 24′ E.) on the S.-wrn. side of the isl.
2. Vessels outward bound wishing to communicate by night
   sig. with this station should commence to attract the notice
   of the station before they get abeam of Balfe Pt. lt., in order
   to afford the station sufficient time to get ready to receive
   the sig. 3. If the sig. be made by fl. lamp, care should be
   taken to keep the lamp pointing direct to the station, and to
   screen all other lts. near it whilst it is being used. 4. At
   night the position of the lower sig.-station will be marked
   by 2 red lts. Feb.

INDIAN OCEAN.—CEYLON.

COLOMBO.—On 1st January, 1909, a new leading-lt. (rear
lt.), occ. white, lt. 7 secs., ecl. 3 secs., vis. from S. 49° E.,
through S., to S. 31° W., R. 12 miles, was to be exh. from a
red lattice steel mast, near the Patent Slip at the S.E. corner
of the harb. This lt. in line S. 14° E. from the F. red lt. at
the N. end of the S.W. breakwater (front lt.) shows over the
extr. nrn. end of the rubble foundation berm of the break-
water-extension works. Vessels approaching the harb. entr.
must keep the F. red lt. open to the S. of this occ. lt. to clear
the works in progress. When the works are completed the
occ. lt. is to be transferred to the head of the breakwater new
protecting-arm. Feb.

CHINA SEA.

Tungsha lt.-v. (31° 8′ N., 121° 59¾′ E.) has been temp. re-
placed by the steam lighter “Wai Tung”), dark colour, black
funnel, 1 derrick, 2 masts, with a black ball on main-
mast, exh. from each yard-arm of yard on mainmast
2 F. white lts. vert. 15 ft. apart, upper lts. elev. 50 ft., R.
10 miles; also carrying a fog-gong, sounded at intervals of
1 min. A white riding-lt. is exh. from the fore stay. Should
the lt.-v. be driven from her station, the usual lts. will not
be exh., but a small red lt. will be shown at each end of the
vessel; the ball will be struck as soon as possible, and, until
struck, it will be surm. by a red flag. Caution.—It may
possibly happen that one or both of the vert. lts. on one
yard-arm may be obse. by the masts or funnel of the lt.-v. to
a vessel that is approaching her. Feb.

WUSUNG RIVER.—The line of the leading-lts. (31° 23¼′ N.,
121° 30′ E.) for crossing the outer bar of the river has been
altered, and the lts. in line, S. 73° W., now lead midway
between the Spit buoy and the lt.-v. Caution.—Owing to
the silting-up of the outer bar near Fort buoy, vessels of
heavy draught must not keep to the srd. of the leading-line
when in this vicinity. The spit srd. of Spit buoy is reported
to be extending, and should be given a wide berth. Feb.

KYAU CHAU BAY.—A masonry beacon, black and white
hor., surm. by a cage, 30 ft. high, is est. in 35° 59¾′ N.,