REVIEWS 
Los temblores en Chile: su causa inmediata y el porqué de sus 
efectos. Por Micurt R. Macuapo, Jeologo del Museo 
Nacional, Miembro de la Comision del Temblor del 16 de 
Agosto de 1906. Santiago de Chile, 1908. 
This paper on earthquakes in Chile is a separate of 28 pages taken 
from some publication not mentioned. It is of special interest just now 
as representing the views and conclusions of a Chilian geologist, who was 
a member of the commission appointed to study the Valparaiso earthquake 
of August 16, 1906, and who traveled over a large part of the region affected 
by that particular earthquake. 
The author says that he failed to find any single center of disturbance, 
but he did find a multitude of areas of high intensity; he thinks it impossible 
to lay down isoseismal lines on a map. Passing over interesting local 
details, at pp. 54, 55 are given the following conclusions which are here 
translated that they may speak for themselves. 
t. In Chile earthquakes are strongest in places located near certain classes 
of eruptive rocks that made their appearance in the Tertiary or about the close 
of the Secondary. These rocks are sometimes found lifting the beds formed during 
the Secondary period. 
2. This rock has a granitoid appearance and a light gray color with greenish 
spots of amphibole. Sometimes it has a porphyroid appearance. In certain 
places it might be called syenite; in others granitic diorite; but it always contains 
amphibole and orthoclase feldspar in varying quantities; and this rock moreover 
is very modern. I think that in Chile this rock should be given the name of the 
earthquake rock or seismic rock. [Here follows a list of localities where this rock 
occurs. | 
3. The earthquake rock is often found cut by gold-bearing shoots, dikes, and 
veins. For this reason the towns, settlements, and walls near places rich in gold, 
whether in the form of veins or gold washings, suffer more than those that do not 
have this precious metal. [Here follows a list of localities that have suffered.] 
4. Buildings and walls on streets parallel with the direction of the earthquake 
rock have suffered very much more than those at right angles to it, where struc- 
tures fall indifferently on either side of their foundations. ... . 
5. I calculate that the maximum destruction was produced in a zone of less 
than four kilometers on both sides of the ridge (cerro) in which the earthquake 
586 
