The Botany of Iceland - 01.12.1914, Page 45

PHYSICAL GEOGRAPHY
229
in origin; that is to sav, they are due to movements and subsi-
dences of large tracts of land bounded by dislocations and fractures
of the ground. In North Iceland, between Skjálfandi and Axar-
fjörður, where the new volcanic tuff district extends to the coast,
violent earthquakes are frequent, especially in the neighbourhood
of the trading-station of Húsavík. The earthquakes of 1755, 1872
and 1885 were especially serious and did great damage in these
districts. At Faxaflói there is another earthquake-area wliere minor
shocks are verv common; they are usually most violent on Rej'kja-
nes, especially in the neiglibourhood of Krisuvík, and at the extreme
point of the peninsula, near the liglithouse. The third earthquake-
area comprises the soulhern lowland area between Reykjanes and
Eyjafjallajökull. This district has frequently suffered from violent
and destructive earthquakes which have caused great loss of humau
life and of property. In modern times the earthquakes of 1784 and
1896 have been especially destructive. The former (Aug. 14—16) com-
pletely ruined 92 farmsteads, and damaged 872 houses and 11
churches. In August and September, 1896, the earthquake shocks
were even more violent. Great chasms were rent in the earlh, some
as long as 15 kin.; water courses were altered and the position of
hot springs clianged; quantities of hugh fragments of rock were
loosened from the mountain-sides; 161 farmsteads were hurled down,
and 155 more were greatly damaged; in fact, every house in this
area sustained some damage. Bj' each of these violent earthquake
shocks a limited tract of land was put in movement. Occasionally,
Nortli Iceland has been shaken by voleanic eruptions whicli origi-
nated under the sea off the north coast of the island; this was the
case in the years 1838, 1899 and 1910.
Hot alkaline springs occur in hundreds in Iceland, scattered
all over the country, sometimes singly, sometimes in groups. At the
present time 677 hot and boiling springs are known in 162 locali-
ties, and tlie majority of them are closely dependent upon the
fracture-systems of the island. Earthquakes exert greal influence
upon these springs; many disappear or are altered, and new ones
are formed. The surfaces of the springs have any temperature uj)
to boiling point. Tepid springs which can be used for bathing are
called “laugar,” boiling springs “hverar.” Some of the latter throw
up jets of water as Geysir does; but otherwise the boiling springs
niay be divided into five classes: (1) springs whicli are constantly