MANILA
BUREAU OF PRINTING
1910
CATALOGUE OF VIOLENT AND DESTRUCTIVE EARTHQUAKES IN THE PHILIPPINES
(1599-1909).
Introduction.--The occasion for publishing this catalogue of
Philippine earthquakes which were of violent and destructive character
has been furnished by a request from Prof. John Milne for a list of
such phenomena, to be included in the General Earthquake Catalogue
which this eminent seismologist is preparing under the auspices of the
British Association for the Advancement of Science. The said general
catalogue has been undertaken with a view toward reducing to
uniformity and completing those published years ago by Robert Mallet
(1859) and Perrey (1844-1871). The form adopted for Professor Milne's
new catalogue is very concise, comprising only the date, intensity,
and region together with principal localities affected. It will
contain only the earthquakes of intensities VII to X according to the
scale of De Rossi-Forel, and these will be divided into three classes:
Class I will be formed by the earthquakes of sufficient force to
produce cracks in buildings and to throw down chimneys; they
correspond to force VII of De Rossi-Forel. Class II consists of the
earthquakes which not only threw down chimneys but also walls and some
weak structures; force VIII of De Rossi-Forel. Class III comprises the
earthquakes which caused general destruction; force IX and X of De
Rossi-Forel. As this classification is as purely conventional as every
other and adopted only in the catalogue mentioned, we do not employ it
in the present catalogue of Philippine earthquakes, but retain the
almost universally adopted scale of De Rossi-Forel. We shall also
present more details as to the towns and buildings damaged, the number
of victims and other disastrous effects than enter into the catalogue
of Professor Milne.
Hence, the differences between the list prepared for Professor Milne
as well as the partial catalogue published in our Monthly Bulletin for
February of the present year consist in the following: (1) This
catalogue contains also several earthquakes whose intensities were
between VI and VII, while in the former only such figure as according
to their effects were decidedly of force VII. (2) The new catalogue is
more complete as to details concerning the towns, etc., which have
been destroyed.
It is to be regretted that we are unable to present here a complete
historical catalogue of all the destruction wrought in the Archipelago
by earthquakes since the time when Legaspi and Urdaneta first set foot
on these shores. But the old chroniclers, who dwell upon the political
happenings with an attention to detail which is occasionally overdone,
were invariably laconic when there was question of earthquakes and
similar natural phenomena; as a rule they were satisfied with
mentioning the occurrence in a general and therefore vague way,
without any attempt at precision as to dates and places. Still the
writers in the Philippines did nothing worse than imitate their
colleagues throughout the rest of the world. This fact is responsible
for the great contrast exhibited by our catalogue as regards the
number and details of earthquakes which occurred prior to 1800,
records of which have been preserved, and the same data for the period
from 1800 to the present time. This same difference is observable in
all catalogues of a similar nature, even in those which cover
phenomena which occurred in Europe. As to the Philippine writers, an
additional excuse is found in the peculiar conditions of life in these
Islands. As far as we know, only two earthquakes which took place
during the period which alone can come under consideration--that is,
since the discovery of the Archipelago--have claimed a considerable
number of victims, and these in the capital, because outside of
Manila--if we except two or three of the principal cities--the
buildings which could become dangerous during an earthquake have
always been few.
Moreover, in a country in which fires consume every year thousands of
dwellings and where the terrible typhoons frequently destroy whole
towns with heavy loss of lives, the damage done by earthquakes has
rarely been so great as to impress those occurrences indelibly upon
the memory. This is beyond doubt one of the reasons why prior to the
beginning of the nineteenth century hardly any data can be found
concerning the numerous earthquakes which during the preceding two
centuries must have occurred in the Visayas and above all on the large
Island of Mindanao.
The first earthquake of which the chronicles contain a mention is that
of 1599. There is no reasonable doubt that during the twenty-eight
years which had then elapsed since the founding of Manila by Legaspi,
several strong and possibly even destructive earthquakes occurred in
this part of Luzon Island, but, as the author of the "Verdadera
relación de la grande destrucción * * * del año 1645" tells us, "when
first founded, Manila consisted of wooden houses roofed with a certain
kind of palm leaves, the same which the natives use in their
buildings." Hence the damage done by these earthquakes must have been
insignificant. Much more terrible were the losses caused by
conflagrations which within a few years twice wiped out the entire
city.
The first Bishop of Manila, Domingo de Salazar, seeing the city
exposed to such general destructions by fire like the one of February
14, 1583, gave the first impulse to the construction of stone
buildings and worked indefatigably in this direction. In person he
explored the surroundings of Manila in quest of stone quarries and by
the middle of the year 1591 he had nearly finished his palace and the
cathedral, when financial difficulties caused a temporary suspension
of the work. At the same time a great number of public and private
buildings were under construction. The enthusiasm for structures of
stone or brick with tile roofs did not diminish during the next fifty
years. The chroniclers tell us that "the Spaniards began to build
their houses of stone and tiles without the so necessary precautions
against earthquakes. * * * Beautiful structures and dwelling houses
were reared, so high and spacious that they resembled palaces;
magnificent churches with lofty and graceful towers, within the walls
of Manila as well as outside of them: all of which made the city very
beautiful and gay and contributed equally to health and pleasure." The
disaster of 1645, commonly called the earthquake of St. Andrew, as it
occurred on the feast of this apostle, November 30, razed nearly every
one of these buildings to the ground, and since then the style and
appearance of buildings has changed greatly throughout the
Archipelago, with a correspondingly great saving of lives in the
subsequent earthquakes.
Masonry arches were henceforth banished from the churches; the heavy
walls of the latter were further strengthened by massive buttresses;
and the towers were given truly enormous substructures. But even with
these precautions there is at present hardly one out of the hundreds
of churches built during the seventeenth and eighteenth centuries
which did not some time or other require important repairs of its
masonry work or even partial reconstruction owing to earthquake
damages. The only structure of this class which thus far has withstood
all convulsions, is the church of St. Agustin, Manila. Nevertheless,
as we have stated before, the chroniclers hardly mention all this
destruction, except in a very general and cursory manner. I do not
hesitate to say: they were accustomed to see similar havoc created
nearly every year in one part of the Archipelago or the other by some
severe typhoon, accompanied by far greater loss of lives and property,
and consequently much more felt by the people than the destruction of
a church, _convento_, municipal building ("tribunal"), one or two
bridges, or other masonry structure.
In the present catalogue our aim has been to present all that is known
of the various violent and destructive earthquakes on record. The
first column of each page contains the ordinal number of the
disturbance for purposes of reference. In the second, the date is
given as accurately as it could be ascertained, Roman numerals being
used to designate the months. Unfortunately, of some earthquakes only
the year is known; of others, the year and month. Of one (No. 32) the
approximate hour has been recorded, but not the day of the month;
while of another (No. 38) the hour has been preserved for posterity,
but whether the phenomenon occurred during February or March, the
records leave undecided. In the third column will be found, in the
first place, the intensity of the disturbance, Roman numerals
representing the degrees of the scale of De Rossi-Forel (I-X); then
the region affected most, and finally the damages caused, if known,
and other information, if available.
In describing the epicentral regions, the present distribution of the
Archipelago into provinces has been used throughout the catalogue.
This division is shown on the first of the two maps of the Philippines
which accompany this catalogue (Plate I). As to the designation
"Benguet" occasionally occurring in the text where provinces are
enumerated, but not found on the map, we beg to offer the excuse that
the region thus named is exceedingly well known in the Philippines as
it contains Baguio, _the_ health resort of the Islands. For the
readers outside of the Archipelago we remark that Benguet is at
present a subprovince of the Mountain Province, of which it forms the
southernmost part. The location of Baguio is shown on the map on Plate
II. A similar remark applies to Lepanto and Bontoc, likewise divisions
of the Mountain Province, whose capitals, Cervantes and Bontoc, are
indicated on the same map.
As we would hardly be justified in assuming that every reader is in
possession of a detailed map of the Philippines, and a knowledge of
the general distribution and the main directions of the principal
mountain systems of an earthquake country is important, we add a
second map on which these data are shown by means of dashes, together
with the most important seismic regions, and the positions of the
principal towns, bays, etc., mentioned in the text. (Plate II.)
Near the left margin of this second map will be found an index of the
seismic regions just mentioned, each of them being represented by its
ordinal number (large Roman figures). Near each of these ordinals is
placed the corresponding number of earthquakes since 1862 contained in
the catalogue (Arabic figures), which is followed, in brackets, by an
analysis of the said number, in which Roman figures designate the
degrees of the earthquake, scale of De Rossi-Forel, while small Arabic
figures, written like exponents, give the number of earthquakes of
each degree of intensity.
In drawing the map on Plate II it was not intended to represent the
epicentric area of every individual earthquake center (which would
have crowded the map beyond reasonable limits), but rather to show the
principal seismic regions. Hence most of these curves contain more
than one focus. The approximate position of each of the latter has,
however, been indicated by a star, while the figure placed close to
the star gives the number of earthquakes which proceeded from the said
center.
A word must be said in apology for the constant use in the following
list of the Spanish word "_convento_." This word which means
monastery, cloister, or convent, is universally used in the
Philippines to designate also the habitation of the clergy attached to
a parish church. Although these are, as a rule, spacious buildings and
were formerly inhabited well-nigh exclusively by friars, they can not
properly be called monasteries. Wherefore, in order to avoid lengthy
circumlocutions, the Spanish word "_convento_" has been retained.
The reader who is not familiar with this country may find it strange
that in reporting earthquake damages so much emphasis appears to be
laid on the harm done to churches and _conventos_. This is easily
explained by the fact that these buildings were often the only
structures within the meizoseismal area, and built nearly everywhere
in the most substantial manner.
In the present catalogue we have also included, by way of an appendix,
the earthquakes which are known to have occurred in the Marianas or
Ladrones group of islands. While their number is too small to warrant
separate publication, we believe that the data concerning them will be
welcome to the earthquake investigator.