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SCIENCE. 



[Vol. XI. No. 270 



and respect for the forces at work. This hne of devastation will 

 again be referred to. 



" Of the towns most damaged, the principal one was Babispe. 

 This typical little Mexican town lies on the west bank'of the Yaqui or 

 'Babispe ' River, as it is there called. The old town is situated on 

 a terrace of the larger mesa, where the new town is. This lower 

 mesa is about thirty feet above the river-level, and about sixty feet 

 below the surface of the upper mesa. The composition of the mesa 

 is, as previously indicated, loosely aggregated drift from the moun- 

 tains. At this place the superficial deposit is very imperfectly con- 

 solidated. Back of the town, to the west, is the Madera range of 

 mountains, a branch of the Teras. The range is directly to the 

 west, and it cannot be over three or four miles away. So far as the 

 method of Mallet in noting angles of emergence, etc., is concerned, 

 I have this to say : there is not the slightest doubt that Mr. Mal- 

 let, or one equally as expert, could have succeeded with it, for there 

 were plenty of fissured walls and overturned objects on which to 

 work. There were all angles of emergence in one building, — 

 cracks ranging from ten degrees to vertical, with several diverging 

 branches. It seems to me that all that can be gathered out of the 

 chaotic state of affairs is, that there has been a considerable shake- 

 up. Apparently the buildings are very substantial, being con- 

 structed of adobes 24x12. These are laid double, which makes 

 all walls 24. inches in width. The average height is 8 to 10 feet ; 

 only one in the town having been greater, and that was 22 feet. 

 The roofs are made by laying rafters, or 'vigas ' as they are called, 

 from one wall to the other ; then covering these with cane, ocotilla, 

 or brush, and that with mud, to a thickness of at least six inches. 

 This makes an extremely heavy roof, but certainly the most suitable 

 one for the climate. Above the vigas is built a slight coping, or 

 fire-wall ; and at intervals are openings with wooden troughs to 

 permit the passage of rain-water. The remains of the building 

 with the four corner posts standing are those of an exceptionally 

 built one ; and a very lucky exception it was in this case, for it saved 

 the lives of four persons who were in it at the time. 



" Of the dwellings destroyed, the major portion were on the 

 northern and eastern side of the plaza. All walls facing the plaza 

 on its west side whose linear direction was north and south were 

 thrown down, falling toward the east. These were from eight to 

 twenty feet in width, averaging pfobably ten feet. Of the houses 

 on the south side of the plaza, which lie at the junction of the ter- 

 race on which the town is, with the foot of the mesa above, none 

 were seriously damaged. They were more or less cracked, but 

 were not prostrated. The church is the most conspicuous monu- 

 ment of the devastating energy of the temblor. It was not, per- 

 haps, as substantial a structure as some of our slighter but more 

 modern civilized buildings, but it certainly could lay claim to the 

 dignity of having withstood the storms and prayers of at least two 

 centuries. 



"The destruction of life was, in my opinion, largely due to the 

 style of architecture. The walls were not held together. In some 

 instances I found the north-and-south walls had separated and let 

 the vigas down into the house on one side. This involved motion 

 of at least a foot. The walls two feet thick, viga laid to cover the 

 entire width was obliged to slip that distance before it could drop. 

 The horizontal cracks at the base of the walls indicated the motion. 

 All damage was done by the first shock. The effect of subsequent 

 tremors was visible only by psychological manifestations. Almost 

 without exception, both sexes gave way to their terror, and devoted 

 themselves to religious e.xercises for the purpose of propitiating the 

 wrath of — so the priest said — a justly offended Deity. 



" Opotu was the next town of any size to suffer considerable in- 

 jury. This place lies south-west of Babispe, on the Yaqui River. 

 It is situated on a bluff of alluvial drift on the bank of the river, some 

 fifty feet above the stream. The axes of the two are pretty much 

 the same as those of Babispe, almost north, south, east, and west ; the 

 population a trifle greater. There were nine people killed outright, 

 and several others injured. I think the intensity of the shock here 

 was fully as great as in Babispe ; but the buildings did not possess 

 the age of those in the latter place, none in Opotu being much over 

 twenty-five years old, while none in Babispe were less than one 

 hundred or two hundred. Perhaps this made less difference than 

 at first sight seems possible. Owing to the manner of construc- 



tion, a certain amount of repairs are constantly necessitated, which 

 would, of course, tend to render them more stable. Of the walls 

 thrown down, with two or three exceptions, all fell to the west- 

 ward, though the upper portion of a few of the east-and-west walls 

 had toppled over towards the south. Walls over twelve feet in 

 length, with their linear axis east and west, suffered entirely in the 

 east and west corners. Where they were shorter, they were 

 thrown down, falling indifferently north or south. The charac- 

 teristic damage received by all houses not prostrated was in the 

 corners. 



" In Fronteras several buildings were destroyed, and one child 

 killed. Fronteras is just off the overflow bottom of the little stream 

 which goes by the name of the ' Fronteras River.' The river is 

 about three-quarters of a mile to the east of the village, and nearly 

 on the same level. A portion of the pueblo is on an isolated drift 

 mesa thirty to fifty feet higher than the remainder. On this mesa 

 is where most of the damage was done. It is not over one hundred 

 feet wide at any portion of it occupied by the houses, consequently 

 presents facilities for amplitude of wave-motion not possessed by 

 the lower town. The Fronteras valley is many miles in width, 

 mesas included, and the alluvial part of it is thoroughly water- 

 soaked. The river-bed skirts rather closely the ranges of moun- 

 tains on the eastern side of the valley. The buildings of Fronteras 

 are of great age, — one to two hundred years. San Bernardino 

 Ranch may be considered as on the same isoseismal. Here were 

 two buildings of adobe, presumably substantial, though slighter 

 than the Mexican-built structures. Both were instantly prostrated 

 at the time of the first shock, fortunately injuring no one. 



" The foregoing makes up the pueblo line of maximum intensity. 

 I wish now again to consider what I have ventured to name the 

 mountain circle of worst disturbance, or the interior line of maxi- 

 mum intensity. The line of demarcation is as distinct as a street 

 in a city. In the order in which I saw them, would be, first, the 

 one on the trail to Babispe, south of Bedregoso. This is from one 

 hundred to three hundred yards in width : it is difficult to tell, as 

 the route is through a deep, narrow cafion, but through there the 

 shattering of the rocks has been extensive. Tons have fallen into 

 the cafions from the cliffs above. Before reaching that point, the 

 disturbance has been moderate, and, after passing, the country has 

 the same appearance. The next place passed having the Jook of 

 equal dynamic energy was far to the south, on the range between 

 Bacadehuachi and Granadas, about halfway, probably a trifle nearer 

 the latter. Here identical phenomena were exhibited, — a narrow 

 line where rocks, shaly and crystalline, have been terribly broken 

 up. . . . On the trail from Opotu to Fronteras, between Nacosart 

 and the Yaqui, and a little more than halfway from Fronteras to 

 Batepito, similar phenomena were seen. 



" The preceding localities form an isoseismal which I have called 

 as above. Let me relate some of the objective symptoms which 

 have determined my opinion in this matter. In the course of my 

 journey, in spite of the condition of Batepito, I came to the con- 

 clusion that the epicentral area was in the Teras Mountains. The 

 principal reason I had for this was the character of phenomena 

 hourly occurring. During all the time I was circling that region, 

 those mountains were continually the seat of various seismic mani- 

 festations. The principal of those was the rumbling, roaring, or, 

 as it seemed to me, the groaning of those massive peaks. Usually 

 this would be succeeded by a more or less severe shock ; but many 

 times the noise would be heard, lasting a minute or more, but no 

 tremor followed. While I was in the neighborhood, certainly, all 

 seismic disturbances had their origin from those mountains, irre- 

 spective of my situation. I had rigged up a seismograph, if such a 

 contrivance can be entitled to the name, consisting of a bullet sus- 

 pended in a large beer-bottle. This, with moderate accuracy, gave 

 me the direction of the vibrations, and all seemed to come from the 

 northern end of the Teras Mountains. Connecting these interior 

 mountain-points, and erecting perpendiculars, the mean epicen- 

 trum is thrown south of the San Bernardino valley. If the Babispe, 

 Opotu, Fronteras, and San Bernardino Ranch are joined, and 

 the same plan pursued, the upper end begins about Pitaicachi, and 

 the lov^fer somewhere near the other mean. 



" Admitting that the central region is about the north end of the 

 Teras, and the southern portion of the San Bernardino valley, the 



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