By Kim Patrick Noyes for History 210
Much has been said and written about the Great Northern California Earthquake of 1906. All too often this event is mistakenly referred to as the 1906 San Francisco Earthquake despite the fact the quake caused significant damage from Humboldt County in the north to Monterey County in the south and the other fact that the fire that followed the quake did the bulk of the damage in San Francisco, NOT the quake itself, but I digress already! This paper is not intended to rehash all the fascinating yet familiar details and statistics related to that tragic tale. This paper is a primer on an aspect of that event that few people know much if anything about.
On April 21, 1906, while San Francisco was still ablaze, then-California governor George C. Pardee appointed the State Earthquake Investigation Commission to, as the name implies, oversee and coordinate an investigation of that great quake that had directly or indirectly caused so much damage across the Bay Area and beyond.
Selected for the commission were A.C. Lawson, chairman of the geology department at U.C. Berkeley who was appointed chairman of this commission; J.C. Branner, professor of geology at Stanford University; G.K. Gilbert, geologist of the U.S. Geological Survey; H.F. Reid, professor of geology at John Hopkins University; Charles Burkhalter, director of the Chabot Observatory at Oakland; W.W. Campbell, director of Lick Observatory; and A.O. Leuschner and George Davidson, both of whom were professors of astronomy at U.C. Berkeley. Most of the commission members were not earthquake researchers at all with the exception of Gilbert and Reid, but this group of men were all competent scientists whom were current or future members of the National Academy of Sciences.
Three days following the appointment of the commission it convened for the first time and formed into two committees. Professor Lawson headed a committee focused upon gathering data regarding surface deformation caused by the quake as well as quake intensities at various localities in the felt area. The other committee headed by Professor Leuschner focused upon collecting data regarding quake arrival times at various localities in the felt area. A few weeks later a third committee, headed by Professor Reid, was formed to establish the geophysics of the event.
By May 31, 1906, not even a full two months after the disaster, the Commission had accumulated enough data to present a preliminary report to Governor Pardee.
Along with the aforementioned members of the commission there were 21 other prominent scientists added to the committees all of whom were giants in their individual fields of study from mathematics to meteorology as well as additional geologists making this one of if not the first multidisciplinary earthquake investigation ever and a model by which subsequent earthquake investigations have been conducted.
This investigation amassed an impressive data set of various types of observations both human and instrumental from interviews with eyewitnesses to topographic surveys utilizing surveying equipment as well as the aforementioned photographic record. Even accounts of animal behavior and marine phenomenon as well as spring behavior related to the quake were collected.
Volume One of the report features all the data collected by the first two committees while Volume Two features the results of the work by the third committee. Volume One is bracketed by a rather remarkable introduction to the general geology of the effected area considering where science was at the time. Volume One culminates with a fascinating climax that details previous significant quakes in California history (up to that time) for contextual purposes such as the 1857 Fort Tejon Quake and the 1868 Great San Francisco Earthquake as it was known until1906. Accompanying the two-volume report is a magnificent atlas/folio of maps of the quake area as well as seismograms of the quake recorded around the world.
Professor Lawson collated all the reports of the contributing investigators his committee and authored Volume One which was published along with the map folio in 1908. Professor Reid authored Volume Two which was published in 1910. Embarrassingly, the State of California was unable and unwilling to pay for this investigation despite its name in the title suggesting otherwise. A generous grant from the Carnegie Institute funded all the expenses of the commission.
The report exhaustively interviewed thousands of witnesses to the quake located all over the northern two-thirds of California and collated that information into a comprehensive listing of quake observations. An excellent example of just one of those observations is found in the excerpt below:
“Stone Canyon Coal Mine. – At the coal mine the shock was very noticeable. The fireman on duty the morning of the earthquake stated that the smoke-stacks, 35 feet high and guyed, swung considerably in various directions. No shifting occurred in the strata of the underground workings. It was stated that the movement was northeast to southwest.” ~ from page 318 in the sub-section of the main section “Isoseismals: Distribution of Apparent Intensity” entitled “Coast Ranges East of the Rift and South of Mount Hamilton, and the West Side of the San Joaquin Valley From Westley to Dudley”.
The quake produced a lot of crazy changes in not only the surface of the earth but also below it that manifested themselves in a variety of ways including in changes in wells and springs as the following excerpt reveals:
“Sunol, Alameda County (R. Crandall). – The level of the ground-water around Sunol was affected considerably. In most of the wells the water rose, some overflowing for a short time. The postmaster gave 4.5 feet as the measured rise of the water in his well. The spring which furnishes the town supply is said to have been diminished by one-fourth of its flow. Two other changes in water supply were reported: one being the starting of a new spring near one of the western Pacific camps in Niles Canyon; the other the rejuvenation of an old sulphur spring near Sunol which had not flowed for many years.” ~ from page 406-407 in the sub-section designated “Record of Springs and Wells Affected”.
There were some rather intriguing animal behaviors related to quake that were nearly as interesting as anything the human animals were doing in the Barbary Coast section of The City at the time of the quake and none more so than the horses as demonstrated in the following excerpt:
“Horses. – Horses whinnied or snorted before the shock and stampeded when the latter was felt, some falling owing to the commotion of the ground. Horses in harness became frightened and ran away, while others stopt and screamed. Some horses with riders in the saddle stumbled and fell; others stood and shivered. A mule near Santa Rosa refused to eat all day. A farmer in the same neighborhood observed his horses moving about, whinnying and snorting, and called to his boy, who was with them, inquiring what was the matter, but before the boy could answer he felt the shock. In a stabler of 30 horses on Alabama Street, San Francisco, all reared, snorted and jumped before the stable-man, who had just fed them, knew the cause of the trouble. Of the 30, all but 5 broke their halters and came toward the stable-man, who had to keep them off with a pitchfork. Several horses at the various engine houses of the San Francisco Fire Department became frightened and broke away from their stalls. In stables generally horses broke away from their stalls, and some failing to break loose lay down.” ~ from page 383-383 in the sub-section designated “Effect of the Earthquake On Animals”.
Even the quake’s effects upon maritime interests was investigated and recorded giving a fascinating perspective to the event that few if any modern people might even consider as evidenced by the following excerpt:
“The Steamer Alliance, off Cape Mendocino, reported by Mr. H.H. Buhne, of Eureka: ‘The captain said she was struck a hard blow, as if she had run on a rock at full speed; time, 5h 15m A.M. Mr. Buhne states that all ships in the harbor at Eureka felt the quake, but in South Bay it was heaviest. One vessel was hurled against the wharf time and again, throwing down piles of lumber and shingles.’” ~ from page 372 in the sub-section designated “Marine Phenomenon”.
The following rather long and seemingly dry excerpt is actually a rather remarkable example of not only a thoroughly exhaustive investigation of a location where San Francisco’s water supply line was severed by the fault but the century-old prose describing the scene is so stunningly articulate in describing the scene that little imagination is required to visualize precisely what is being described:
“Just above the northern end of Crystal Springs Lake, a 44-inch water main made of iron 0.125 inch thick runs up the hill from the lake valley in a direction about North 28 degrees East. This line is buried all the way under several feet of soil. The fault crosses it at the base of the hill, in its North 37 degrees West course, thus making an acute angle of 65 degrees with the pipe line. At the intersection of the fault and the pipe line, the heavy rivets of the pipe were torn out all the way around at a section joint and the two sections were jammed into one another a distance of 4 feet 4 inches. In addition to the telescoping of this pipe, a slight change in course was induced, so that the northeast end trended one or two degrees more toward the east than the other end. This was shown by the fact that the broken ends did not fit into each other squarely. There was no lateral displacement, the whole movement having been taken up by telescoping, but there was a bending of the pipes at the point of the break, as mentioned. The main part of the pipe, at the distance from the fault, must have moved with the land. At the fault trace there was a bend amounting to one or two degrees. Supposing the bowing to be simple, this amount indicated that the land must have carried the pipe the distance represented by the telescoping, or about 10 feet, within 300 to 500 feet of the fault on one side, and that beyond such a point the pipe must have preserved its normal course. As a matter of fact, this same pipe was broken on the northeast side of the fault about 400 feet further up the hill. The break occurred at the junction of 2 sections, the rivets having been sheered off and part of the trim torn away at the rivet holes. The ends were pulled apart 3.375 inches. Here the pipe resumed its former course, but owing to the slight amount of the pipe displayed by the excavation, it was impossible to see whether a return bend occurred or not. Beyond the break the direction was as before measured, approximately North 28 degrees East. No such break occurred on the southwest side of the fault. A crack was formed in the earth at right angles to the pipe for several yards on either side of the break.”
As evidenced by this very short list taken from a report several hundred pages long this investigation left no chunk of rubble unturned in search for a better understanding of what happened with an eye towards mitigation and prediction in the future. These efforts have born much fruit as of over a century later, although much more so in the realm of mitigation than prediction which is still an unachieved goal although limited forecasting is now sometimes possible.
Out of this investigation emerged two already well-regarded stars in the field of geology in the sub-discipline of seismology.
The preeminent American geologist Harry Fielding Reid was a rather remarkable character well beyond his time in his profession. He was the first to articulate the now-accepted Theory of Elastic Rebound, something that we now take for granted in the field of seismology and geophysics.
As a result of Fielding’s observations of and conclusions from the 1906 event he proceeded to define a fault as "a crack in the Earth's crust caused by strain from movement deep below. Each side of the fault is held tightly in place by friction until enough energy is built up to overcome it. The release is so swift that it creates seismic waves. This is followed by decades of quiet during which the strain builds up again." This perfectly describes Elastic Rebound Theory even in current terms as well as that of fault action which seems so obvious now but back then it was rather revolutionary. California’s greatest disaster to date provided much of the impetus and inspiration for realizing some of the most basic tenants of the geophysics of our planet (and by extension all rocky planets like our own).
Grove Karl Gilbert was another preeminent geologist on the commission who was the report’s chief photographer and is considered one of the fathers of the sub-discipline of geomorphology which is the study of landforms and how they are formed and he was an even bigger name in the sub-discipline of planetary geology. The body of photographs he took along much of the quake’s rupture zone in the days immediately following the quake, often using his wife for scale, formed a remarkable photographic record detailing the after effects of the quake and remains useful to this day as a record of not only what happened at the time but is a useful template against which to measure subsequent changes over time at the locations he photographed. Gilbert to this day is still the only two-term president of the Geological Society of America.
In summary, the landmark Report of the State Earthquake Investigation Committee which was chartered to investigate the Great Northern California Earthquake of April 18, 1906, was a remarkable scientific undertaking that was well ahead of its time and set a new benchmark for future scientific investigations and helped further the human understanding of the geophysics of earthquakes and laid some of the foundation upon which the soon to emerge Theory of Plate Tectonics would soon be built.
Fini
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