302 
DR. TEMPEST ANDERSON ON THE ERUPTIONS OF THE SOUFRIERE IN 
The General Sequence of Volcanic Phenomena, etc.* 
In addition to the volcanic and seismic occurrences noticed under this heading, 
mention ought to be made of the great eruption of the volcano of Santa Maria in 
Guatemala, on October 24, 25, 26, 1902, news of which had scarcely arrived in Europe 
at the time when Part I. went to press. Owing to the extremely remote and 
inaccessible position of the volcano the eruption did not attract the notice it deserved, 
it was not examined at the time by any English or American man of science, although 
Professor Karl Sapper, of Tubingen, has published an account.! 
This eruption was of the same explosive type as those of St. Vincent and 
Martinique, but much more violent. An entirely new crater about three-quarters of 
a mile in its longer diameter was formed, and the south side of the volcano (which 
was supposed to have been extinct) was blown away. 
I venture in conclusion to submit the following speculation as to the depth of the 
volcanic foci beneath St. Vincent and Martinique. The chimneys of the two 
volcanoes appear to have some connection underground as may be inferred from the 
following considerations. The eruptions have been repeatedly either simultaneous or 
so nearly so that the difference in time might be accounted for by the magma being 
delayed in travelling through a devious and perhaps branching passage or system of 
passages, blocked in different degrees by various obstructions. The eruptions have 
been of the same type, viz., explosive without the effusion of lava, and of a rather 
special variety of that type, the Pelean.| The chemical composition of the ejecta is 
not more different than could be explained by the interaction between the magma at 
a high temperature and the walls of the passages, supposing them to intersect various 
strata. It seems, therefore, natural to conclude that the two volcanoes are at the ends 
of two branches of one common passage, and it is not unreasonable to suppose that 
these branches divide at an angle not very obtuse and consequently at a great depth. 
If the two volcanoes were supplied from a comparatively superficial laccolite or 
intrusive sheet of molten matter extending widely under the whole district at no 
very great distance below, why did not an eruption also take place in the Island of 
St. Lucia, which is in a direct line between the two volcanoes and in which there is 
an active Soufriere, or through the sea bottom, which attains a depth of 10,000 feet 
both on the Atlantic and Caribbean side of the chain of islands ? 
* Part I., p. 532. 
t Dr. Karl Sapper, ‘In den Ynlcangebieten Mittelamerikas und Westindiens,’Stuttgart, 1905, and 
several smaller articles. 
t I visited and examined the volcano in January, 1907, and have published an account of this visit in 
the ‘Geographical Journal,’ April, 1908. 
| For a discussion of this see Part I., p. 499, and for the details of the coincidence of these eruptions 
see p. 532. 
