One hundred years of petroleum exploration and development in the Los Angeles region have produced a rich legacy of geological and geophysical data -- a legacy that the oil industry has spent billions of dollars to obtain.
It would seem obvious that all of this data could be of great value in earthquake research and other geoscience studies. Right?
Well, maybe not -- and certainly not obvious to many people today. Given the changing and often reduced profile of the oil industry in the trembling state, why would they know?
Even worse, company merging, downsizing and relocating are taking many oil industry players out of the California game completely -- and putting an increasing amount of geological data at risk of disappearing in a trash bin.
But there's hope for the recovering and storing of such valuable data, in no small part because there's at least one geologist who has pioneered the transferring of knowledge gained from those exploring oil to those interested in understanding earthquakes: Thomas L. Wright.
Wright, now a consultant residing in San Anselmo, Calif., was recognized for his efforts at the AAPG annual meeting in New Orleans when he received this year's AAPG Michel T. Halbouty Human Needs Award.
The Halbouty Award is presented annually for outstanding application of geology to the benefit of human needs, recognizing scientific excellence.
That description combination fits Wright perfectly -- and his work may be even more important in decades to come because of the knowledge and problem-solving energy he's applying to an earthquake-prone part of the world.
No-Fault Driving
Wright, a preeminent authority on the geology of the Los Angeles Basin, earned his B.S. and M.S. degrees in geology from Stanford University and entered the oil industry in 1952. He has a long and varied career, mainly with Chevron.
Wright first came to the realization that the geologic knowledge gained from exploration could have broader purposes beyond the oil industry back in the early 1950s.
"Local petroleum geologists had formed an improbable alliance with anti-nuclear activists to oppose the construction of a nuclear power plant on the coast near Malibu (California)," Wright recalled.
"Those of us engaged in the fiercely competitive urban exploration some 20 miles east of the site knew that the coastline followed a fault zone with at least 10,000 feet of vertical displacement, some of it probably Quaternary."
During a hearing, which included many objections from oil industry representatives, "a supporter of the project pulled out an early 1950s guidebook from the state division of mines and geology that didn't show a fault," Wright said. "'Here's my authority,'" the supporter said.
The reason for the absent fault?
"The draftsman had the choice of either drawing the state highway on the map, or the fault running beneath it," Wright said. "That was the quality of geological thinking going on in decisions like this at that time."
This project was brought to a halt, but only because the California senator at that time was former Hollywood actor George Murphy, who was friends with another former actor who was a vice president at a major oil company.
"It was a deal where politics took precedence over science," Wright said.
The Added Dimension
A few years later, in February 1971, the problem reappeared. The M=6.5 sylmar earthquake involved a fault zone, the eastern Santa Susana fault, that separated crystalline basement from Quaternary sediments.
Immediately adjacent to the fault, a 1950 exploratory well had penetrated more than 12,000 feet of Quaternary.
"That data was published and well known to local petroleum geologists," Wright said, "yet neither we nor local seismologists had made the obvious connection -- 12,000 feet of Quaternary offset means a very active, potentially dangerous fault.
"Clearly, we needed to communicate what we knew to the seismologists puzzling over southern California's earthquake hazards."
Wright became increasingly involved in making this knowledge connection.
"Tom has pursued his youthful interests in earthquakes and the out-of-doors to make significant contributions to our present knowledge of seismic hazards, and to our industry's responses to environmental challenges," said Halbouty citationist Donald Clarke.
In 1994, for example, when the Northridge earthquake struck, Wright was the first to identify the "unknown" source fault. He was then asked to lead a campaign to obtain industry subsurface and geophysical data for use in earthquake research. He devoted much of the next several years to that task.
Why has this subsurface knowledge not been shared routinely?
"During the years since the 1971 earthquake, I had come to realize that access to data was not the only barrier to a better understanding of earthquakes," he replied. "Earth science had ceded the study of earthquakes to seismologists, and most of those worthy folks were physicists, mathematicians and instrument makers. They thought in terms of the velocity of earthquake waves through rock -- about 5 to 8 km/second -- but the processes that cause earthquakes operate at plate-motion speeds in the range of 5 cm/year."
That difference, he continued, some eleven orders of magnitude, exemplified the contrast between a seismologist's approach to earthquakes and that of a geologist.
"California petroleum geologists know that the physical properties of crystal rocks show great lateral variation, that specimens in a rock-mechanics lab do not behave the same as rocks deep in the subsurface and that crystal structure has evolved over geologic time in ways that are seldom simple," he said.
"Our four-dimensional approach to the earth needed to be integrated into the seismologists' studies."
Saving the Data
To foster information transfer and dialogue between petroleum geologists and the earthquake research community, special symposia were held at the 1993 and 1994 Pacific Section conventions.
A follow-up session, hosted by Chevron Research, was organized for late January 1994, just 10 days before the Northridge earthquake struck. A poster session was added that displayed the seismic lines in the region of the epicenter.
"In his workshop summation, John Crowell stressed that much valuable data was at risk of being lost as the major companies continued their exodus from California," Wright said. "He called for a concerted effort to obtain industry seismic and well data for earthquake research, and 'volunteered' me to lead that effort."
Wright adds that, six years later the effort is far from complete. What has been salvaged are some 8,500 boxes of Chevron's California well files.
Out of some 40,000 drilled wells, the records of some 500-1,000 are worth saving.
To archive and make accessible this and additional information will, it is hoped, be accomplished by a special center at California State University-Long Beach. This would involve a faculty position and M.S. students who would be trained in this area.
"When (and if) the necessary endowment is obtained," Wright said, "it will indeed make possible an 'outstanding application of geology to the benefit of human needs.'"