From October 27 to 28, 1971, the Joint Committee on Atomic Energy of the U.S. Congress held hearings on the Status of Current Technology to Identify Seismic Events as Natural or Man Made. James Brune of the University of California at San Diego submitted a statement endorsed by a number of scientists knowledgeable about seismic monitoring regarding the verification of an underground test ban. They were all familiar with the results of the Ms-mb method used for seismic identification as well as work presented by several of us at the Woods Hole conference in 1970.
The written statements of those scientists were published in the Hearings Before the Subcommittee on Arms Control, International Law and Organization of the Committee on Foreign Relations of the U.S. Senate—Toward a Comprehensive Nuclear Test Ban Treaty—on May 15, 1972. Their statements described recent advances that improved the detection of signals from underground nuclear explosions and earthquakes down to magnitude mb 4 and yields of about two kilotons in hard rock. Those methods could be used to identify (differentiate) those events with high reliability upon deployment of adequate numbers of modern instruments. This, of course, was better than the threshold of mb 4.75 proposed in 1963. This work was praised by members of the Committee on Foreign Relations but not by several members of the Joint Committee on Atomic Energy.
Lukasik, the director of ARPA, testified at the Joint Committee’s hearings in October 1971 that we knew by then how to identify explosions down to a magnitude mb of 4.5 (7 to 14 kilotons in hard rock) and that, in principle, seismic discrimination around mb 4.0 (1 to 2 kt) appeared feasible. But he, like members of the Joint Committee, stressed that it would take time to verify such improvements.
I testified before the same subcommittee of the Senate Foreign Relations Committee on May 15, 1972, my first testimony before Congress. I was nervous. All of the other people who testified were seasoned, well-experienced witnesses and speakers. I was invited to testify about the results of the HGLP experiment and other advances in distinguishing the signals of underground explosions from those of earthquakes. Dr. Herbert Scoville, a test ban proponent who had worked at the CIA in the early 1960s and later at the U.S. Arms Control and Disarmament Agency (ACDA), recommended me to the subcommittee. I believe Evernden did as well.
My conclusions were very similar to those of the above group of scientists. We all stated that major advances in seismic identification had been made in the previous decade. Referring to the plate tectonic revolution of the late 1960s, I stated, “During the last ten years the earth sciences, which include seismology, have experienced a renaissance in the understanding of large-scale earth processes such as why earthquakes occur where they do, and what types of movements occur in various parts of the world.”
Few seismologists outside of ARPA and AFTAC, including me, were aware at the time of just how good the U.S. classified capabilities were. The findings reported in my congressional testimony of 1972, as well as those of the scientists who wrote to Congress in 1971, were based on unclassified results. In addition, because we made no assumptions about future data that might be obtained from seismic stations within the USSR and China, we were of necessity discussing observations at distances greater than about 1850 miles (3000 km).
In my testimony, I also discussed the false alarm problem—that is, small earthquakes being misidentified as underground explosions. I stated that 99 percent of earthquakes in Eurasia (Europe plus Asia) of magnitude 4.5 and larger could be positively identified as such.
I addressed several possible evasion schemes, including detonating small nuclear explosions near the times of earthquakes, conducting multiple explosions so that their Ms value appeared to be that of an earthquake, and using decoupled (muffled) testing in large underground cavities. I stated that research on better processing of seismic signals might render the first two schemes less useful for evasive testing, which shortly turned out to be the case. I also pointed out that cavity decoupling—large explosions set off in deep underground chambers—had not been tested for a nuclear explosion larger than a fraction of a kiloton.
Hide-in-earthquake ceased to be a successful evasion method decades ago. Simple data processing methods allowed the signal from an explosion of interest to remain large while those from distant earthquakes were reduced in size. For example, the signal from a large earthquake in the eastern part of the Soviet Union hid that of the small explosion at the Soviets’ Eastern Kazakhstan test site on the normal seismic recording (see upper part of figure 11.1), but playing out the recordings at a higher frequency clearly brought out the signal from the small explosion (see the lower part of that figure).
Detonating multiple nuclear explosions close in time to one another so that their signals were like that of an earthquake also is no longer a viable evasion scheme. Recording data over many periods and frequencies, as with the HGLP instruments, eliminated multiple explosions as a threat. While they might be made to look like an earthquake at one frequency, they could not at other frequencies.
Senator Edmund Muskie, the chair of the subcommittee, asked me only one question: “Are ARPA seismologists and private seismologists far apart in their assessment of the problem?” I answered, “I think not so far as detection and discrimination. I think the disagreement mainly resolves around the evasion issue.” Muskie went on to include for the record the statement made by the group of scientists in April 1972. I think he may have expected me to launch into a criticism of the removal of the summary written by Evernden for the published volume on the Woods Hole conference, which I did not do. Muskie already knew about its removal.
When I returned to Lamont, I received a phone call from William Best of the Air Force Office of Scientific Research, who oversaw the HGLP project. He said that an official at ARPA, who was present at my testimony, said that I had done well, probably meaning I had not criticized ARPA. I found out later that person, a geologist, strongly believed that testing in huge cavities in salt could muffle large nuclear explosions.
I vowed to myself that in future testimony I would state clearly in my conclusions that a full test ban was verifiable, desirable, and in the national interest. Prior to the deletion of Evernden’s summary for the Woods Hole conference report in 1971 and my Senate testimony of 1972, I was of the naive belief that advances in research on seismic monitoring soon would be translated politically into a full test ban.
In the subcommittee hearings of May 15, 1972, Philip Farley, acting director of the U.S. Arms Control and Disarmament Agency, presented the current views of the executive branch on the question of further limitations on nuclear tests. He said that he could confirm that the administration’s position remains as stated by President Nixon in 1969: “The United States supports the conclusion of a comprehensive test ban, adequately verified.” His statement gave no indication of what constituted adequate or sufficient verification.
Dr. Herbert York, dean of graduate studies at UC San Diego, head of the Livermore Lab from 1952 to 1958, and a top Pentagon scientist in the Eisenhower administration, also testified in May 1972. He prefaced his remarks at the 1972 hearing by quoting from an interview with the chairman of the Atomic Energy Commission, James Schlesinger, an opponent of a full test ban. Schlesinger said, “We have very much improved our capability to monitor events in the Soviet Union, but the question of the desirability of a test ban goes far beyond the question of monitoring what the Soviets are doing. The real question is, given the changed nature of the opposing forces in this era of negotiations, whether it is desirable to cease testing.” York went on to say, “I agree with his position. I have for some time felt that the real question is whether it is desirable.” York then summarized his testimony: “[W]e could have had and should have had a comprehensive test ban ten years ago.” He discussed the main objections raised by others a decade before and found them largely wanting: (1) concern about a Soviet ABM (anti-ballistic missile) capability, (2) breakthroughs and surprises, (3) improvements in design factors such as yield-to-weight ratio of warheads on intercontinental missiles, and (4) our understanding of weapons effects. When asked about the prospects for a Comprehensive Test Ban Treaty (CTBT) in 1972 to halt development of multiple independently targetable reentry vehicles (MIRVs) for Soviet missiles, he said it was probably too late. At that time the Soviet Union likely was testing weapons for their MIRV land- and sea-based missiles. The United States had tested them earlier.
The CTBT hearings of 1971 and 1972 did not lead to negotiations for a full test ban treaty. The idea did not resurface in the U.S. government until 1977, when the Carter administration entered into negotiations with the Soviet Union and Britain. Following the Limited Test Ban Treaty (LTBT) of 1963, however, progress was made in other arms control negotiations, such as limits on the numbers of delivery vehicles for nuclear weapons and anti-ballistic missiles.
NUCLEAR NONPROLIFERATION TREATY
Four years of multinational negotiations finally led to the Nonproliferation Treaty (NPT) that was signed in 1968 and entered into force on March 5, 1970, for a duration of twenty-five years. It was the most important arms control agreement following the Limited Test Ban Treaty. The NPT was discriminatory by design, in that it divided countries into two groups: the acknowledged nuclear weapons states and nonnuclear countries. The weapons states pledged not to transfer nuclear weapons to other nations and not to assist any nation in making or acquiring them. The nonnuclear states agreed not to make or receive nuclear weapons and to allow the International Atomic Energy Agency (IAEA) to monitor their compliance. The parties to the NPT agreed to share the benefits of peaceful uses of nuclear energy.
The NPT requires parties to the treaty to “seek to achieve the discontinuance of all test explosions of nuclear weapons for all time and to continue negotiations to this end” and to “pursue negotiations in good faith on effective measures relating to the cessation of the nuclear arms race at an early date and to nuclear disarmament.” Understandably, during each five-year review conference for the NPT, many of the nonnuclear states that signed the NPT sharply criticized the weapons states for not achieving a CTBT. A few countries, including India, Israel, and Pakistan, did not sign the NPT. North Korea signed but withdrew prior to its first nuclear test. India claimed that its first test, which was underground, was for peaceful purposes, which many doubted. India signed the Limited Test Ban Treaty, but neither the NPT nor the CTBT.
The NPT was up for renewal on its twenty-fifth anniversary in 1995. In return for extending it to infinite duration, the nonnuclear states extracted from the weapons states a pledge to reach a CTBT in 1996. The latter complied with their pledge. The NPT was extended indefinitely in 1995.
MONITORING AFTERSHOCKS OF A LARGE UNDERGROUND NUCLEAR EXPLOSION
A group of us from Lamont monitored aftershocks generated by Benham, one of the largest (1150 kt) underground nuclear explosions at the Nevada Test Site on December 19, 1968. Seismologists at the University of Nevada claimed that a previous large explosion at NTS had triggered earthquakes 25 miles (40 km) away. Their evidence was not very strong. Peter Molnar and Klaus Jacob drove a Lamont van, which had a small area for working and sleeping, to Nevada to monitor activity for a week before the United States detonated Benham. They operated six portable instruments in abandoned mines on the east side of the test site within 50 to 110 miles (75 to 175 km) of Benham.
I flew to Las Vegas on the day of the explosion and drove a rental car about 100 miles (160 km) to the town of Alamo, where Molnar and Jacob were staying. Halfway to Alamo, snow started to fall heavily, a weather condition that was supposed to be ruled out when deciding to fire such a large explosion. Those responsible at the test site probably wanted to complete the Benham test before the upcoming holidays. Fortunately, Benham did not vent—that is, leak radioactive materials into the atmosphere.
In a 1969 paper, Molnar, Jacob, and I found no significant change in the numbers of small earthquakes within 15 miles (25 km) of each instrument from before to after Benham. The explosion triggered numerous very small aftershocks, but they were confined to within about 6 miles (10 km) of its epicenter.
In late December 1968, after monitoring Benham, Jacob and I decided to move the portable Lamont instruments to Death Valley, California, just west of the Nevada border, to monitor several active faults. Molnar returned to Lamont. Our van was having mechanical problems, so we decided to stop midway for repairs in Las Vegas.
Because the number of working daylight hours was short in late December, we typically got up well before daylight for breakfast and ate dinner after dark. We went to a casino in Las Vegas near our motel for breakfast the next morning about 5 AM. TV sets had been set up so that patrons could see the splashdown in the Pacific of the Apollo flight that first flew around the moon but did not land on it. We were happy to see the successful landing while having breakfast, but most gamblers were oblivious to the exciting scenes on the TVs.
After we set up our instruments in Death Valley later that day, it was too cold to sleep in the van, so we drove back uphill to a motel in tiny Death Valley Junction, the same route on which mule teams hauled borax to trains at the Junction. Those trains and the mule teams had long disappeared. The next morning, December 31, at 5 AM, we went for breakfast at the only diner in town. A man came over to our table and remarked that we must not be from around there and was delighted to hear we were from New York. He told us that his wife, Marta Becket, would be dancing a ballet that evening, New Year’s Eve, in town at the Amargosa Opera House and invited us to join him for the performance. It proved to be a memorable evening. The year before, as Marta and her husband were on their way from Los Angeles to Las Vegas, they passed a recreation hall in town. She decided to rent it, renaming it Amargosa, its original name.
Klaus indicated that he would be ten minutes or so late for the performance because he wanted to call his sister in Massachusetts to wish her Happy New Year. Becket’s husband said, “No problem; we’ll wait for you to start.” We turned out to be the only people who stayed for the full performance. One family came late and left early. Becket’s husband pulled the curtain, worked the lights, and played recorded music. On the back wall of the small theater, he and Marta had painted a copy of Velasquez’s Las Meninas, in which the young infanta Margaret Theresa is surrounded by her entourage of maids of honor, a chaperone, a bodyguard, two dwarfs, and a dog. They said they went ahead with ballet performances even if no one else came; they had Las Meninas for spectators. The Opera House, now on the National Register of Historic Places, was discovered several years later and became successful. Marta’s final show was in 2012.
Afterward, Klaus and I were invited to have a glass of champagne with Marta and her husband. About an hour before midnight, as we stood around celebrating, a frightened woman’s face appeared at a window of their home. She said her husband, who was to get out of prison at midnight, had vowed to kill a man, and she needed help in finding him. As Ms. Becket’s husband was about to join her, Marta implored him not to go, but he said, “These are our neighbors, and I need to help them.” So off he went. We headed back to our motel room and slept soundly as the New Year arrived.