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This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library.

This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library.

Seismologists from Kazakhstan, Russia, and the United States have rescued the Soviet-era archive of nuclear explosion seismograms recorded at Borovoye in northern Kazakhstan during the period 1966–1996. The signals had been stored on about 8000 magnetic tapes, which were held at the recording observatory. After hundreds of man-years of work, these digital waveforms together with significant metadata are now available via the project URL, namely http://www.ldeo.columbia.edu/res/pi/Monitoring/Data/ as a modern open database, of use to diverse communities. Three different sets of recording systems were operated at Borovoye, each using several different seismometers and different gain levels. For some explosions, more than twenty different channels of data are available. A first data release, in 2001, contained numerous glitches and lacked many instrument responses, but could still be used for measuring accurate arrival times and for comparison of the strengths of different types of seismic waves. The project URL also links to our second major data release, for nuclear explosions in Eurasia recorded in Borovoye, in which the data have been deglitched, all instrument responses have been included, and recording systems are described in detail. This second dataset consists of more than 3700 waveforms (digital seismograms) from almost 500 nuclear explosions in Eurasia, many of them recorded at regional distances. It is important as a training set for the development and evaluation of seismological methods of discriminating between earthquakes and underground explosions, and can be used for assessment of three-dimensional models of the Earth’s interior structure.

Earthquake-induced drifts in buildings can be reduced by adding secondary moment frames to provide post-yield stiffness. It is desirable to have secondary frames that will remain elastic up to the expected drifts, but this is challenging to accomplish with traditional configurations. Most steel moment frames will yield at drifts of 1 to 2 percent even though drifts of 3 to 4 percent are expected for ductile systems under the maximum consider earthquake. For steel moment frames, the elastic drift limit can be increased by providing pinned connections (bolted web) at selected beam-column joints. This paper discusses the characteristics and use of high-yield-drift (HYD) steel moment frames that remain elastic up to 4 percent drift. High-yield-drift frames dramatically improve the economy of steel dual systems. In this study, HYD moment frames were compared to traditional steel moment frames with the same steel weight. The HYD frames were found to achieve greater strength while using half the number moment connections, due to inherent efficiencies in the configurations. Also, since the moment connections in HYD frames have minimal ductility demands, special connection details are not necessary. Fewer moment connections with minimal ductility demands will dramatically decrease the cost of secondary moment frames, improving the economy of dual systems. Non-linear response history analyses were used to demonstrate how HYD moment frames can be used in conjunction with buckling restrained braced frames, self-centering braced frames, and conventional moment frames. Case study frames were analyzed under both design-basis (DBE) and maximum-considered earthquakes (MCE), with maximum and residual drifts results presented. Recommendations are given for the use of HYD moment frames and directions for future research.

We have attempted to detect seismic signals from small explosions in North Korea on five specific days in 2010 that feature in scenarios proposed by De Geer. We searched the seismic data recorded by station MDJ in northeastern China, applying three-component cross-correlation methods using signals from known explosions as templates. We assess the capability of this method of detection, and of simpler methods, all of which failed to find seismic signals that would be expected if De Geer's scenarios were valid. We conclude that no well-coupled underground explosion above about a ton occurred near the North Korea test site on these five days and that any explosion would have to be very small (local magnitude less than about 2) to escape detection.

Fundamental information about the Universe is encoded in anisotropies of the Cosmic Microwave Background (CMB) radiation. To make full use of this information, an experiment must image the entire sky with the angular resolution, sensitivity, and spectral coverage necessary to reach the limits set by cosmic variance on angular scales >~10'. Recent progress in detector technology allows this to be achieved by a properly designed space mission that fits well within the scope of NASA's Medium-class Explorer program. An essential component of the mission design is an observing strategy that minimizes systematic effects due to instrumental offset drifts. The detector advances make possible a `spin chopping' approach that has significant technical and scientific advantages over the strategy used by COBE, which reconstructed an image of the sky via inversion of a large matrix of differential measurements. The advantages include increased angular resolution, increased sensitivity, and simplicity of instrumentation and spacecraft operations. For the parameters typical of experiments like the Primordial Structures Investigation (PSI) and the Far InfraRed Explorer (FIRE), we show that the spin-chopping strategy produces images of the sky and power spectra of CMB anisotropies that contain no significant systematic artifacts., 15 pages, including 8 figures. Full resolution and colour versions of simulations and full versions of the preprint available at ftp://omega.jpl.nasa.gov/pub/wwwdir/PSI/papers.htm . Further details of PSI and FIRE are available at http://astrophysics.jpl.nasa.gov/PSI/ and http://caseymac.jpl.nasa.gov/fire/fire.html, respectively

Buckling-restrained braced frame performance at high drifts is improved by providing beam splices that reduce demands in the gusset regions. Existing experimental data only consider web splices without a slab present. An alternative top-flange splice, proposed by others, was investigated experimentally and numerically. Two full-scale top-flange beam splices from a prototype frame were tested using the qualifying buckling-restrained brace frame cyclic loading protocol. During experimental testing, the gusset connection regions remained essentially undamaged through multiple cycles at 0.06rad drift. The splice plates experienced low inelastic strains but fatigue analyses indicate they could withstand over fourteen similar loading histories without requiring replacement. Finite element models were used to investigate the influence of slabs on connections with web splices or top-flange splices. When slabs were considered, the top-flange splice transmitted over seventy-percent less moment than the web splice.

Modern cosmology has sharpened questions posed for millennia about the origin of our cosmic habitat. The age-old questions have been transformed into two pressing issues primed for attack in the coming decade: How did the Universe begin? and What physical laws govern the Universe at the highest energies? The clearest window onto these questions is the pattern of polarization in the Cosmic Microwave Background (CMB), which is uniquely sensitive to primordial gravity waves. A detection of the special pattern produced by gravity waves would be not only an unprecedented discovery, but also a direct probe of physics at the earliest observable instants of our Universe. Experiments which map CMB polarization over the coming decade will lead us on our first steps towards answering these age-old questions.

Buckling-restrained braced frames (BRBFs) are often used in steel buildings to resist seismic loads; however, BRBF ductility can be limited by poor performance of the beam-column-gusset regions. Additionally, the concentric brace configuration in BRBFs can limit the use of architectural features, such as doors, windows, or halls. BRBFs with braces in eccentric configurations (called BRBF-Es) may accommodate architectural features similar to eccentrically braced frames, and limit damage to the connection regions through 1) the use of beam splices and 2) separation of the column-to-gusset connection which prevents pinching of the brace gusset plate. Similar to concentric BRBFs, seismic forces in BRBF-Es are dissipated through axial yielding of the buckling-restrained braces, while surrounding elements remain essentially elastic. In this study, the system-level and component-level dynamic performances of conventional BRBF systems are compared with those of BRBF-E systems. Multi-directional dynamic analyses are performed on 5-story BRBF and BRBF-E systems to compare drift demands and local connection demands. Modeling techniques are validated using experimental data for BRBFs. Results indicate similar stiffness between the BRBF and BRBF-E systems; however, with the BRBF-E, gusset connection stresses are greatly reduced due to the beam splices and eccentricity between the braced connection and column.

The variation in maximum rupture extent of large shallow earthquakes in circum-Pacific subduction zones is interpreted in the context of the asperity model of stress distribution on the fault plane. Comparison of the historic record of large earthquakes in different zones indicates that four fundamental categories of behavior are observed. These are: (1) the Chile-type regular occurrence of great ruptures spanning more than 500 km; (2) the Aleutians-type variation in rupture extent with occasional ruptures up to 500 km long, and temporal clustering of large events; (3) the Kurile-type repeated failure over a limited zone of 100–300 km length in isolated events; and (4) the Marianas-type absence of large earthquakes. Southern Chile, Alaska, Southern Kamchatka, and possibly the Central Aleutians are grouped in the first category. The Rat Island portion of the Aleutians, Colombia, Southwest Japan, and the Solomon Islands zones demonstrate the temporal variation of rupture length and multiple earthquake sequences that characterize category 2. The New Hebrides and Middle America have earthquake clustering on a more moderate scale, and are intermediate between categories 2 and 3. Category 3 includes the Kurile Islands, Northeast Japan, Peru and Central Chile. Zones lacking large earthquakes (category 4) include the Marianas, Izu-Bonin, and large portions of Tonga-Kermadec. By loosely grouping each subduction zone into these categories and comparing the general range in behavior with a simple fault model, which is used in a numerical simulation, the parameters governing large earthquake development are clarified. Interpretation of the four categories in terms of asperity distribution and interaction permits some inferences of the nature of stress distribution in particular zones. Two factors appear to dominate in the development of large earthquake failure zones; the nature and degree of coupling on the fault contact, and the extent of lateral segmentation of the subduction zone by transverse stress barriers. Strong coupling and uniform stress distribution on the fault plane produces larger events, whereas more heterogeneous stress distributions produce smaller ruptures and temporal variation in rupture length. Segmentation of the subduction zone that may result in stress barriers affecting rupture length is produced by subduction of transverse structures such as aseismic ridges, and is reflected by submarine canyons and geometric variations in trench configuration.

Various seismicity patterns before major earthquakes have been reported in the literature. They include foreshocks (broad sense), preseismic quiescence, precursory swarms, and doughnut patterns. Although many earthquakes are preceded by all, or some, of these patterns, their detail differ significantly from event to event. In order to examine the details of seismicity patterns on as uniform a basis as possible, we made space-time plots of seismicity for many large earthquakes by using the NOAA and JMA catalogs. Among various seismicity patterns, preseismic quiescence appears most common, the case for the 1978 Oaxaca earthquake being the most prominent. Although the nature of other patterns varies from event to event, a common physical mechanism may be responsible for these patterns; details of the pattern are probably controlled by the tectonic environment (fault geometry, strain rate) and the heterogeneity of the fault plane. Here a simple asperity model is introduced to explain these seismicity patterns. In this model, a fault plane with an asperity is divided into a number of subfaults. The subfaults within the asperity are, on the average, stronger than those in the surrounding weak zone. As the tectonic stress increases, the subfaults in the weak zone break in the form of background small earthquakes. If the frequency distribution of the strength of the subfaults has a sharp peak, a precursory swarm occurs. By this time, most of the subfaults in the weak zone are broken and the fault plane becomes seismically quiet. As the tectonic stress increases further, eventually the asperity breaks and sympathetic displacement occurs on the entire fault zone in the form of the main shock. Foreshocks do or do not occur depending upon the distribution of the strength of the subfaults within the asperity. Since the spatio-temporal change in the stress on the fault plane is most likely to dictate the change in seismicity patterns, detailed analysis of seismicity patterns would provide a most direct clue to the state of stress in the fault zone. However, because of the large variation from event to event, seismicity pattern alone is not a definitive tool for earthquake prediction; measurements of other physical parameters such as the spectra, the mechanism and the wave forms of the background events should be made concurrently.

The U.S. pelagic longline fishery catches 98% of domestic swordfish landings but is also one of the three fisheries most affecting federally protected sea turtles (Crowder and Myers 2001, Witherington et al 2009). Bycatch by fisheries is considered the main anthropogenic threat to sea turtles (NRC 1990). Accurate and precise bycatch estimates are imperative for sea turtle conservation and appropriate fishery management. However, estimation is complicated by only 8% observer coverage of fishing and data that are hierarchical in structure (i.e., multiple sets per trip), zero-heavy (i.e., bycatch is rare), and often overdispersed (i.e., larger variance than expected). Therefore, I evaluated two predominant bycatch estimation methods, the delta-lognormal method and generalized linear models, and investigated improvements in uncertainty incorporation. I constructed a simulation model to evaluate bycatch estimation at two spatial scales under ten spatial models of sea turtle, fishing set, and observer distributions. Results indicated that distributing observers relative to fishing effort and using the delta-lognormal-strata method was most appropriate. The delta-lognormal-strata 95% confidence interval (CI) was wider than statistically appropriate. The delta-lognormal-all sets pooled 95% CI was narrower but simulated bycatch was above the CI too frequently. Thus, I developed a bycatch estimate risk distribution to incorporate uncertainty in bycatch estimates. It gives managers access to the entire distribution of bycatch estimates and their choice of any risk level. Results support the management agency's observer distribution and estimation method but suggest a new procedure to incorporate uncertainty. This study is also informative for many similar datasets. Master of Science