On Shaky Ground

by Nance, John J. ;

  A short while before, Migliaccio had been profoundly shocked while viewing one of the 8 mm movies taken by a Chena crew member when the faces of several people in one particular vehicle (which had driven safely off the dock moments before the quake) rolled across the screen: They were his wife and children. Ralph Migliaccio had not known they were anywhere near the dock that day—and had not known how close he had come to losing them.

  7. A local newspaper article (as quoted in “Land Use Planning After Earthquakes”) by Larry Makinson reported the changes, saying that the preliminary draft of the municipality’s Comprehensive Development Plan echoed both the warnings of the consultants and of Task Force 9. Among its recommendations for policies to be followed by the local government:

  “The portions of the Comprehensive Development Plan which have been identified as being susceptible to earthquake-induced landslides and given a high risk classification by Task Force Nine must be respected. Any development in these areas should conform with the specifications governing the development of such areas.

  “That recommendation was deleted in its entirety … [as] was any mention of the word ‘earthquake.’ Privately, the planners say little has been done with the recommendations of the federal task force … because of simple political pressure.

  “But politicians, after all, often reflect the attitudes of their constituents. And people in Anchorage seem to have largely forgotten the Great Alaskan Earthquake of 1964, except as history.”

  Chapter 24

  1. The first settlers in Parkfield—three brothers who arrived in 1854—had settled down just in time for the 1857 Parkfield quake (which may have been the trigger to the great Fort Tejon earthquake of the same period).

  2. In fact, if the trends of movement on all eighteen base lines measured by Duane Hamann’s careful work were to be magnified logarithmically and sped up many times over by a computer graphic display, the points surrounding Parkfield that it monitors would be seen to wiggle, undulate, and twitch almost like the surface of a bowl of very cold, very rubbery Jell-O tapped in the middle. The overall trend lines give the seismologists back in Menlo Park a continuous indication of the fault’s movements at the surface, and it is those measurements which they hope will detect any slippage which might occur suddenly in the days or weeks before the next quake. In the meantime, the multiyear examination of the undulating surface has provided a wealth of supportive information for other seismic observations. After the 1983 Coalinga quake, for instance, the Pacific plate side of the fault actually began reverse movement of a few millimeters for a short time. Exactly what that means, however, is still unclear.

  3. The reflectors, which he also helped mount, are so optically pure that a two-cell flashlight beam aimed exactly at one causes a highly visible spot of light to shine back, even from the most distant reflector, 9.2 kilometers to the south.

  4. Hamann himself, a dedicated teacher and schoolmaster of the one-room (though modern and well-equipped) Parkfield School, has been a familiar fixture in the small community for eighteen years. The mixture of his limitless enthusiasm and the unending trail of television crews and journalists who have made the pilgrimage to Parkfield have also made Duane and his pupils media stars of sorts—and that in turn has made a demanding life a bit more fun.

  5. This is called a deterministic forecast, or one in which it is stated that an earthquake either will or won’t occur on a given date and at a given time, rather than the current tentative realm of “probabilistic” forecasts, such as stating that there is a one-in-five chance assigned to the possibility of a particular quake’s occurring within a given area.

  6. In early 1988, Dr. Zoback’s drilling project was suspended because of cuts in the National Science Foundation’s budget. The tragedy was that the project had only reached 11,420 feet down, and had several thousand feet to go before penetrating the segment of the San Andreas Fault system that the scientists had most wanted to study. While some of the information obtained in the first 11,000 feet showed a contradictory lack of stress parallel to the fault, and considerable stress across the fault (a discovery called “surprising” by those associated with the project), the drill bit would have needed to penetrate below 16,000 feet to provide the hard-core, meaningful information they were really after on whether or not the fault system is under extreme parallel tension as postulated. While one newspaper report labeled the initial findings as putting the prevailing theories of strain-release cycles in some doubt, scientists associated with the project pointed out that the “cross-the-fault” stress field simply meant that Los Angeles is probably in even more danger than previously believed from small fault systems underneath the L.A. basin.

  Chapter 25

  1. The shaken group would be joined momentarily by the only teacher who had been inside the school, a teacher who had done exactly what she had taught her students to do so many, many times in earthquake preparation classes: duck and cover, get under a desk, and wait. Within a minute after the shaking stopped, she gingerly made her way down the stairs and outside—to the considerable relief of the others, who had just noticed she was missing.

  2. Lupe had died instantly, but her death was a horrifying reminder of how many lethal dangers an earthquake can place into motion in the space of a heartbeat—and how much work remains to be done on older structures which incorporate them.

  3. Three others died of heart attacks, and many hundreds of minor injuries sent a flood of people to hospitals throughout the area.

  Chapter 26

  1. The April 13, 1949, earthquake was centered between Olympia and Tacoma and registered Ms 7.1, killing eight, and causing $25 million of damage—most of it confined to marshy, alluvial, or filled ground similar to that underlying the heaviest damage in Mexico City’s 1985 quake. Nearly all the tall buildings in Olympia (the state capital) were damaged. On April 29, 1965, a Ms 6.5 quake occurred between Seattle and Tacoma, causing $12.5 million of damage, most of it in Seattle. Four persons were killed, and three died of apparent heart attacks as a result of the quake.

  2. The bill would have formed an independent Seismic Safety Commission modeled after the California Seismic Safety Commission. Governor Booth Gardner vetoed the bill on the ground that the Department of Emergency Management already had the authority to carry out the commission’s functions. (The Department of Emergency Management has since been reorganized as a division within the Department of Community Development, and earthquake preparedness is predictably a poorly funded, tiny adjunct to that agency’s agenda.) While it was clear that the governor agreed with the goals and expected them to be fulfilled by the existing state agency, mixing hazard mitigation with emergency preparedness (or management) has been historically a lost cause. Only a specifically dedicated state function directed to the earthquake preparedness and hazard reduction programs can adequately focus a staff’s undivided attention on the essence of the problem. The very same arguments against a new governmental program were raised for five years in a row by the Nixon and Ford administrations against the passage of the national Earthquake Hazard Reduction Act: the justification that the same authority was already in the hands of existing agencies.

  Appendix 1

  Demystifying Earthquake Magnitude Ratings and Scales

  We have all heard the phrase “Richter Scale” applied to measurements of an earthquake’s size, usually in the form of a number (such as 6.4, or 7.2). In fact, Dr. Charles Richter of Caltech formulated the original scale that has come to bear his name to measure only California earthquakes by finding a way to standardize the meanings of the various instruments (seismographs) and the various ways they recorded the picture of seismic waves. Before that time, comparing different seismograph readings was difficult because the waves grow less energetic as the miles from the epicenter increase, and thus the very same earthquake could appear much more intense on seismograph drums closer to the epicenter than on drums hundreds of miles away. Richter, along with Dr. Beno Guttenberg, devised a way of adj
usting the readings from a specific type of seismograph for distance and other factors to arrive at a standard “apples-to-apples” reading that would describe the strength of a California quake. This became the “Richter Scale.” Unhappily, though, the scale can be applied to only one area, and since the seismographs are measuring just one range of the wavelengths (approximately 300 meters to 6 kilometers, or .1 to 2.0 cycle per second waves), the scale represents merely a “snapshot” of a small part of the picture (seismologists call it “spectra”) of an earthquake. For one thing, areas outside of California respond differently (the eastern United States, for instance, transmits seismic waves with an efficiency increase one order of magnitude greater than California subterranean real estate). And another major problem with, the Richter Scale is that the larger an earthquake becomes, the more energy it transmits through the ground in wavelengths that cannot be registered faithfully by looking at Richter’s target wavelengths.

  Therefore, additional means of measuring the strength of an earthquake and expressing it in digital, logarithmic terms were needed, and that gave rise to additional scales, the more important of which are listed below. All these scales are logarithmic, so that a 1.0 increase means a ten times increase in the movement of the ground beneath that particular seismometer, and suggests roughly a thirty times increase in energy release.

  ML Local Magnitude: Essentially, this is Dr. Richter’s scale, most accurately applied when dealing with California quakes. It is still quite useful today for describing smaller and more moderate earthquakes, but it is not useful in earthquakes classed as “Great.”

  Ms Surface-Wave Magnitude: This scale was formulated by Dr. Guttenberg to describe quakes at distant locations. The scale principally measures surface waves with a 20-second period, or a wavelength of approximately sixty kilometers.

  MB Body-Wave Magnitude: Also formulated by Dr. Guttenberg, this scale measures the type of waves that pass through the interior—the body—of the planet, and that have a period of between 1 to 10 seconds (although the USGS applies a standard under this heading of measuring only wave periods of 0.1 to 3.0 seconds).

  Mw Moment-Magnitude: (Sometimes expressed as Mm): This is today perhaps the most meaningful scale for large and great earthquakes, in that it combines a measurement of total energy release with the magnitude (amplitude) of the earthquake waves themselves. The measurement takes into account the surface area of the fault that moved to cause the quake, plus the average displacement of the fault plane, and the rigidity of the material of the fault. A seismic moment, Mo, is the result, and when that is combined with an energy-magnitude formula, the result is a common means of measuring the greatest earthquakes on the planet, such as Alaska, 1964, and Chile, 1960. This is the work of K. Aki and Hiroo Kanamori, among others, and is very recent—which is why great earthquakes, such as that in Alaska in 1964, which were once related in the Ms 8.5 range have been upgraded to an Mw rating in the low 9’s. This is also the magnitude quake that the Pacific Northwest may be facing.

  While these scales all have the similarity of being logarithmic and measuring seismic waves, they measure radiation of an earthquake at separate frequency bands. Therefore, while some readings may be equivalent between an Ms and an Mw, for instance, other comparisons may be wildly different for the very same earthquake. Therefore, there has always been a need to find another way to measure the effects on man and his structures that would bypass these technical problems in dealing with different-size quakes, and that is best done with the Modified Mercalli Intensity Scale, which basically measures the results of ground shaking in human and structural terms, assigns a Roman-numeral value, and provides an apples-to-apples comparison of resulting damage not possible with diverse magnitude scales.

  Modified Mercalli Intensity Scale of 1931 (Abridged)

  (After Wood and Neumann, 1931, as printed in “Earthquake Hazards, Risk, and Mitigation in South Carolina and the Southeastern United States” [see citation under References, Chapter 227]).

  I.

  Not felt except by a very few under favorable circumstances.

  II.

  Felt only by a few persons at rest, especially on upper floors of

  buildings. Delicately suspended objects may swing.

  III.

  Felt quite noticeably indoors, especially on upper floors of buildings,

  but many people do not recognize it as an earthquake. Standing

  motor cars may rock slightly. Vibration like passing of truck.

  Duration estimated.

  IV.

  During the day felt indoors by many, outdoors by few. At night some

  awakened. Dishes, windows, doors disturbed; walls made cracking

  sound. Sensation like heavy truck striking building; standing motor

  cars rocked noticeably.

  V.

  Felt by nearly everyone; many awakened. Some dishes, windows,

  etc., broken; a few instances of cracked plaster; unstable objects

  overturned. Disturbance of trees, poles, and other tall objects

  sometimes noticed. Pendulum clocks may stop.

  VI.

  Felt by all; many frightened and run outdoors. Some heavy furniture

  moved; a few instances of fallen plaster or damaged chimneys.

  Damage slight.

  VII.

  Everybody runs outdoors. Damage negligible in buildings of

  good design and construction; slight to moderate in well-built

  ordinary structures; considerable in poorly built or badly designed

  structures; some chimneys broken. Noticed by persons driving

  motor cars.

  VIII.

  Damage slight in specially designed structures; considerable

  in ordinary substantial buildings with partial collapse; great in

  poorly built structures. Panel walls thrown out of frame

  structures. Fall of chimneys, factory stacks, columns, monuments,

  walls. Heavy furniture overturned. Sand and mud ejected in small

  amounts. Changes in well water. Persons driving motor cars

  disturbed.

  IX.

  Damage considerable in specially designed structures; well-designed

  framed structures thrown out of plumb; great in substantial

  buildings, with partial collapse. Buildings shifted off foundations.

  Ground cracked conspicuously. Underground pipes broken.

  X.

  Some well-built wooden structures destroyed; most masonry and

  frame structures destroyed with foundations; ground badly cracked.

  Rails bent. Landslides considerable from river banks and steep slopes.

  Shifted sand and mud. Water splashes (slopped) over banks.

  XI.

  Few, if any (masonry) structures remain standing. Bridges destroyed.

  Broad fissures in ground. Underground pipe lines completely out of

  service. Earth slumps, land slips in soft ground. Rails bent greatly.

  XII.

  Damage total. Waves seen on ground surfaces. Lines of sight and

  level distorted. Objects thrown upward into the air.

  Appendix 2

  “Okay, so what do I do?”

  While writing your congressional delegation about additional funding for research and preparedness efforts and a national earthquake insurance bill are urgently needed actions, there are things you and your family can do right now to greatly—and I do mean greatly—enhance your prospects of coming through a great earthquake (or a lesser one) unscathed.

  First, understand that most casualties are caused by falling objects and debris:

  •

  Partial building collapse, such as toppling chimneys, falling bricks, ceiling plaster, or light fixtures.

  •

  Flying glass.

  •

  Overturned bookcases, furniture, appliances.

  •

  Fires from broken chimneys, broken ga
s lines, overturned gas water heaters, and other causes.

  Step One

  Survey your home for possible hazards:

  •

  Locate all the heavy furniture, bookcases, filing cabinets, and other items that could fall on you or your children if the foundation begins jerking around beneath the structure you call home.

  •

  Identify domestic “seismic bombs”; gas water heaters that can topple, gas lines that have no cutoff wrench permanently placed beside them, or fireplaces without a working fire extinguisher nearby.

  •

  Determine which parts of your home would provide the most protection from falling objects and breaking glass in an earthquake.

  •

  Determine whether there are trees, power lines, tile roofs, over-hangs, or other hazards that could fall on you if you ran outside during a major earthquake.

  Step Two

  Hold a Family Preparedness Meeting:

  •

  Decide on a plan if the ground starts shaking.

  •

  Brief everyone—especially children—on where to go and where NOT to go.

  •

  Brief everyone on the necessity to avoid glass windows and doors, which could shatter.

  •

  Determine what can be done to make the home safer.

  Step Three

  Preventative Steps in the Home:

  •

  Screw or bolt heavy free-standing furniture to the floor and hanging pictures to the wall.