||Issue Date: 5 / 2006
Andrew Lawson: Discoverer of the San Andreas Fault
The San Andreas Fault was discovered only a decade before the l906 disaster in San Francisco--an event that changed how scientists look at earthquakes. Earthquakes were thought incidental to ecology when Andrew Lawson started his career more than a century ago. A popular textbook described them as "a shudder of the cuticle" of the earth. Their cause was unknown. But a few scientists thought they might be related to the great cracks and faults seen cutting through the surface rocks.
Andrew Lawson is best known for discovering and naming the San
Andreas Fault in 1895, when much was still unknown about
earthquakes, the "shudder[s] of the cuticle of the earth."
(Courtesy John Dvorak)
Click image to enlarge.
In 1890 Lawson joined the faculty of the University of California, which then had only one campus (in Berkeley), and started studying the surrounding geology. He was immediately attracted to the Coastal Ranges south of San Francisco where, thirty years earlier, Josiah Whitney, for whom Mount Whitney, the highest peak in the contiguous United States, is named, described the intrusion of granite into Miocene sediments. Such an interaction should have heated and altered the sediments, but Lawson found no such evidence. Instead, he noticed that the boundary between the granite and the sediments was remarkably straight, running along one side of a long valley. He recognized the boundary as a fault where the granite and sediments had slid pass each other. Lawson gave the discovery no special significance, except to assign the name of the valley to the fault: San Andreas.
That was in 1895. In his report, Lawson gave what was then a reasonable interpretation for what he saw. He reasoned that because the sediments were younger and had formed above the granite, they must have dropped down while the granite moved up. Such vertical movement is common in mountain ranges, though, again, Lawson found no evidence, such as offset rock layers. He commented on another peculiar feature. Rivers and valleys usually run away from mountain crests, but the San Andreas Valley ran obliquely across the Coastal Ranges and was aligned with another long valley, Crystal Springs. Again, he had no explanation.
Earthquakes were long known in California before Lawson started his work A large earthquake struck southern California in 1857, and two earthquakes damaged San Francisco, one in 1865 and another in 1868. The latter collapsed buildings and killed several people. But at the time, scientists thought a large earthquake could strike almost anywhere. In the short history of the United States, major ones had struck Boston near St. Louis and Charleston, South Carolina. So there was no particular concern when five quick earthquakes shook the bay area on December 1, 1904, causing chandeliers to swing and collapsing a few brick chimneys. When asked about these specific tremors, Lawson apparently forgot recent history and dismissed the possibility of all imminent large earthquakes, claiming "earthquakes in this locality have never been of a very violent nature." His opinion soon changed.
At 5:12 a.m. on April 18, 1906, a powerful earthquake rocked San Francisco for almost a minute, killing thousands and, with the subsequent fires, causing hundreds of minions of dollars in damage. The shaking was felt from southern Oregon to Los Angeles and as far east as Nevada. In Berkeley, the shaking was much less than in San Francisco, and so Lawson did not immediately realize the severity of the quake. But he soon heard of the destruction and saw smoke rising from fires across the bay.
The next day, Lawson sent a telegraph to Governor George Pardee who was in Oakland directing a relief effort. In the message, Lawson asked the governor to appoint a scientific commission to investigate the earthquake, arguing that it "would have a beneficial effect on the public mind." The governor agreed. Two days later, he announced a "Committee of Inquiry" consisting of nine members, including Lawson.
The committee first met on April 24 and elected Lawson its chairman. There were probably private concerns about the choice. Lawson was known for his quick temper and for treating colleagues harshly. Charles Richter, who would later devise the familiar earthquake-magnitude scale, remembered Lawson as having a "vitriolic personality." Another geologist, who said he once "suffered" though a seminar given by Lawson, thought the Berkeley professor was "opinionated and intolerant." Nevertheless, as chairman Lawson was a model of diplomacy, urging other members to complete their work and finding reasonable alternatives when they failed. The result was a preliminary report published six weeks after the earthquake. In it Lawson concluded that the earthquake was caused by movement along a fault that stretched from Point Arena north of San Francisco to San Juan Bautista far to the south, a distance of almost two hundred miles and included the section of the fault he discovered in 1895. But the direction of movement was unexpected. Geologists then thought faults were associated mainly with upward growth of mountains or the downward warping of the formed ocean basins. But the movement in 1906 was horizontal in places as much as twenty-one feet, such that land west of the San Andreas Fault had shifted to the northwest. It was a mystery that would remain for sixty years.
A year later, Lawson completed a massive report, one still frequently cited, that detailed the fault movement, complete with hundreds of photographs, and included an atlas that showed the fault trace and the different degrees of destruction across California. At the end he made recommendations about rebuilding in an obvious seismic zone. Specifically, he urged that public buildings, especially schools, be constructed on firm ground and that other buildings be "thoroughly bonded and well cemented" and "of honest construction." Such recommendations ran counter to the campaign to rebuild San Francisco quickly.
Three days after the earthquake, while the city was still burning, Governor Pardee announced to the nation that "the destruction was wrought far more by fire than by earthquake." Two weeks later, the Real Estate Board of San Francisco passed a resolution pledging its members to speak of the disaster as "the great Fire,'" not "the great Earthquake." Collectively, politicians and businessmen felt that any mention of the earthquake, including the establishment of building codes, would slow reinvestment and recovery of the city.
The political pressure continued for years. In 1916, when the first statewide geologic map for California was issued, it appeared without earthquake faults--not even the San Andreas.
For their part, Lawson and other geologists organized the Seismological Society of America, and Lawson was elected its president in 1909. But it was impossible to find funds to support teaching and research. The first course in seismology in the United States was at the University of California in 1911, later disguised as a geology course. The first building code to include requirements for seismic shaking was approved by the California legislature in 1927, prompted by an earthquake in Santa Barbara that killed thirteen people and caused millions of dollars in damage. Not until the 1913 Long Beach earthquake, when several school buildings collapsed, did the legislature require state inspection of school construction.
Lawson's influence did not end there. In 1915 he and others started a degree program in oil exploration and refinery, educating the first generation of petroleum engineers. During the 1930s he was hired to determine the position of the piers for the Golden Gate Bridge. After the first caisson was sunk through sea sediments, he climbed down into a hundred-foot deep shaft and examined the bedrock. When he reappeared, he "was surrounded by engineers and an anxious press. He told them, "I put my hands on the living rock, and it is sound." The bedrock would support the planned sixty-ton bridge.
Lawson was away on a trip when a fire swept through his
section of Berkeley in 1923, destroying more than six hundred
houses. Everything in his quakeproof, fireproof house
(specially designed by local architect Bernard Maybeck),
survived, including his library. (Courtesy John Dvorak)
Click image to enlarge.
But the true nature of the San Andreas Fault would not be known until after Lawson's death in 1952, when in the 1960s the plate-tectonic revolution identified the San Andreas fault as a horizontal-sliding, transform fault dividing the North America and Pacific plate. But, had Lawson lived, he might have remained unconvinced. In 1939, when shown a model demonstrating how thermal convection inside the earth could shift the earth's surface--the driving force for plate tectonics--Lawson responded, "I may be gullible, but not enough to swallow this poppycock."
The Lawson house
After the 1906 disaster, Lawson was determined to build a quakeproof, fireproof house. For the design, he hired local architect Bernard Maybeck who, years later, would design the Palace of Fine Arts in San Francisco.
Maybeck saw a parallel between San Francisco and the ancient Roman city of Pompeii. Both were located near the sea and enjoyed a mild climate. And both were destroyed by a powerful natural force--Pompeii by an eruption of Vesuvius. And so, Maybeck decided to model Lawson's new house on the spacious Pompeian villa, adapting it to the wooded hills around Berkeley.
The Lawson house sits on a hillside near the University of California, situated to have a commanding view of the bay and of Oakland and San Francisco. It is constructed of reinforced concrete, a relatively new material at the time. The result is a monolithic structure. The key elements are rectangles arranged symmetrically along a central axis. Maybeck positioned and sized windows to lie along diagonals of the rectangles. The roof is a single, thin slab of concrete set at a low angle. Following Pompeii, Maybeck covered the building with pink and buff-colored plaster, then inscribed the plaster with diamond patterns and embedded it with colored glass squares.
The house has withstood all subsequent earthquakes, though none has shaken with the violence of the 1906 event. The two-storied house is located near the Hayward fault which, according to seismologists, has a sixty-two percent chance of a major earthquake by 2033.
Lawson was away on a trip when a fire swept through his section of Berkeley in 1923, destroying more than six hundred houses. Unfortunately, some well-intentioned neighbors broke into his house and removed pieces of furniture, hoping to save them. The furniture later burned. Everything that had remained in the house survived, including his library.
Lawson lived in the house until 1931 when he married twenty-two-year-old Isabel Collins, a recent graduate of McGill University in Montreal. They soon moved to another section of Berkeley. The couple had a son in 1949, when Lawson was eighty-seven. Lawson died in 1952.
For more information, visit The World & I Online archives:
--"Earthquakes," by T.A. Heppenheimer, January 1987 (Article #12395)
--"Earthquakes: Improving the Odds for Survival," by Ian G. Buckle, June 1990 (Article #17769)
--"Charity Done Right: How San Francisco Recovered From the 1906 Earthquake and Fire," by Daniel T. Oliver, January 2001 (Article #21305)
John Dvorak started his professional career studying
earthquakes for the U.S. Geological Survey in Menlo Park,
California. The 1906 earthquake has held a special fascination
for him because it dramatically changed the perception of
earthquakes, which were once thought inconsequential in
forming earth's landforms. After studying earthquakes, Dvorak
shifted to volcanoes, then to stars. Today he operates a
telescope at Mauna Kea in Hawaii.