Rose Parade Seismology: Signatures of Floats and Bands on Optical Fiber

The 2020 Rose Parade in Pasadena, California, was recorded by the Pasadena distributed acoustic sensing array, which utilizes the underground telecom fiber optic cables as sensors. The floats and bands generate remarkable broadband seismic signatures that can be captured at meters’ resolution

Rapid development of spiral garnets during subduction zone metamorphism revealed from high-resolution Sm-Nd garnet geochronology

Multiple studies have applied zoned garnet geochronology to place temporal constraints on the rates of metamorphism and deformation during orogenesis. We report new high-resolution isotope dilution–thermal ionization mass spectrometry Sm-Nd isochron ages on concentric growth zones from microstructurally and thermodynamically characterized garnets from the Betic Cordillera, southern Spain. Our ages for the garnet core (13.64 ± 0.31 Ma), mantle (13.41 ± 0.37 Ma), and rim (13.34 ± 0.45 Ma) indicate rapid garnet growth and are consistent with published garnet ages interpreted to reflect high-pressure metamorphism in the region. Thermodynamic analysis indicates garnets grew during subduction at ∼1.5–2.0 GPa and 570–600 °C. The core to rim duration of spiral garnet growth was just a few hundred thousand years. While other zoned garnet studies have shown similar rapid growth in subduction zone settings, this is the first documentation of such rapid growth of a spiral garnet. Combining this garnet growth duration with the magnitude of spiral inclusion trail curvature, we compute a strain rate of ∼10−13 s−1, an order of magnitude faster than all previous spiral garnet studies. We interpret that these spiral garnets recorded a rapid pulse of deformation and strain during the final stages of subduction and incipient exhumation.Spanish grants CGL2015–65602-R (AEI-FEDER), P18-RT-3275, and B-RNM-301-UGR18 (Junta de Andaucía/FEDER)U.S. National Science Foundation grants PIRE-1545903 and EAR-194665

Distributed acoustic sensing for seismic activity monitoring

Continuous, real-time monitoring of surface seismic activity around the globe is of great interest for acquiring new insight into global tomography analyses and for recognition of seismic patterns leading to potentially hazardous situations. The already-existing telecommunication fiber optic network arises as an ideal solution for this application, owing to its ubiquity and the capacity of optical fibers to perform distributed, highly sensitive monitoring of vibrations at relatively low cost (ultra-high density of point sensors available with minimal deployment of new equipment). This perspective article discusses early approaches on the application of fiber-optic distributed acoustic sensors (DASs) for seismic activity monitoring. The benefits and potential impact of DAS technology in these kinds of applications are here illustrated with new experimental results on teleseism monitoring based on a specific approach: the so-called chirped-pulse DAS. This technology offers promising prospects for the field of seismic tomography due to its appealing properties in terms of simplicity, consistent sensitivity across sensing channels, and robustness. Furthermore, we also report on several signal processing techniques readily applicable to chirped-pulse DAS recordings for extracting relevant seismic information from ambient acoustic noise. The outcome presented here may serve as a foundation for a novel conception for ubiquitous seismic monitoring with minimal investment

Distributed acoustic sensing for seismic activity monitoring

Continuous, real-time monitoring of surface seismic activity around the globe is of great interest for acquiring new insight into global tomography analyses and for recognition of seismic patterns leading to potentially hazardous situations. The already-existing telecommunication fiber optic network arises as an ideal solution for this application, owing to its ubiquity and the capacity of optical fibers to perform distributed, highly sensitive monitoring of vibrations at relatively low cost (ultra-high density of point sensors available with minimal deployment of new equipment). This perspective article discusses early approaches on the application of fiber-optic distributed acoustic sensors (DASs) for seismic activity monitoring. The benefits and potential impact of DAS technology in these kinds of applications are here illustrated with new experimental results on teleseism monitoring based on a specific approach: the so-called chirped-pulse DAS. This technology offers promising prospects for the field of seismic tomography due to its appealing properties in terms of simplicity, consistent sensitivity across sensing channels, and robustness. Furthermore, we also report on several signal processing techniques readily applicable to chirped-pulse DAS recordings for extracting relevant seismic information from ambient acoustic noise. The outcome presented here may serve as a foundation for a novel conception for ubiquitous seismic monitoring with minimal investment

Teleseisms monitoring using chirped-pulse φOTDR

Monitoring of seismic activity around the word is a topic of high interest for the analysis and understanding of deep Earth dynamics. However, the deployment of a homogeneous network of seismic stations both onshore and offshore poses a strong economic challenge that makes this solution practically inviable. Using the pre-existing fiber optical network for seismic monitoring arises as an excellent solution with important advantages in terms of ubiquity and cost. In this communication, we present the detection of an M8.2 earthquake occurred in Fiji Island using distributed acoustic sensing based on chirped-pulse φOTDR. Two sensors were placed simultaneously at two different locations at >9,000 km from the earthquake epicenter: a metropolitan area and a submarine environment. The recorded data is postprocessed using a 2D linear filter to cancel out environmental noise. The resulting signals are compared with the signals acquired by nearby seismometers. The attained good matching between the recorded data and the seismometer data shows the strong potential of the use of the already-deployed communication fiber network for teleseism monitoring

In situ detection of boron by ChemCam on Mars

We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater

Teleseisms monitoring using chirped-pulse φOTDR

Monitoring of seismic activity around the word is a topic of high interest for the analysis and understanding of deep Earth dynamics. However, the deployment of a homogeneous network of seismic stations both onshore and offshore poses a strong economic challenge that makes this solution practically inviable. Using the pre-existing fiber optical network for seismic monitoring arises as an excellent solution with important advantages in terms of ubiquity and cost. In this communication, we present the detection of an M8.2 earthquake occurred in Fiji Island using distributed acoustic sensing based on chirped-pulse φOTDR. Two sensors were placed simultaneously at two different locations at >9,000 km from the earthquake epicenter: a metropolitan area and a submarine environment. The recorded data is postprocessed using a 2D linear filter to cancel out environmental noise. The resulting signals are compared with the signals acquired by nearby seismometers. The attained good matching between the recorded data and the seismometer data shows the strong potential of the use of the already-deployed communication fiber network for teleseism monitoring

Fiber-Optic Observations of Internal Waves and Tides

13 pages, 5 figures, supporting information https://doi.org/10.1029/2023JC019980.-- Data Availability Statement: All 4.5 days of DAS data from the Strait of Gibraltar necessary to reproduce Figure 2 and the 3 days of DAS data from Gran Canaria necessary to reproduce Figures 3 and 4 are available through the CaltechDATA repository (Williams et al., 2023). Figures were produced using GMT6 (Wessel et al., 2019)Although typically used to measure dynamic strain from seismic and acoustic waves, Rayleigh-based distributed acoustic sensing (DAS) is also sensitive to temperature, offering longer range and higher sensitivity to small temperature perturbations than conventional Raman-based distributed temperature sensing. Here, we demonstrate that ocean-bottom DAS can be employed to study internal wave and tide dynamics in the bottom boundary layer, a region of enhanced ocean mixing but scarce observations. First, we show temperature transients up to about 4 K from a power cable in the Strait of Gibraltar south of Spain, associated with passing trains of internal solitary waves in water depth <200 m. Second, we show the propagation of thermal fronts associated with the nonlinear internal tide on the near-critical slope of the island of Gran Canaria, off the coast of West Africa, with perturbations up to about 2 K at 1-km depth and 0.2 K at 2.5-km depth. With spatial averaging, we also recover a signal proportional to the barotropic tidal pressure, including the lunar fortnightly variation. In addition to applications in observational physical oceanography, our results suggest that contemporary chirped-pulse DAS possesses sufficient long-period sensitivity for seafloor geodesy and tsunami monitoring if ocean temperature variations can be separated.Funding for this project was provided through the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S), the Spanish MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR Program under projects PSI ref. PLEC2021-007875 and TREMORS ref. CPP2021-008869, the Spanish MCIN/AEI/10.13039/501100011033 and FEDER Program under projects PID2021-128000OB-C21 and PID2021-128000OB-C22, and the European Innovation Council under Grant SAFE: ref. 101098992. E. F. W. was supported by a National Science Foundation Graduate Research Fellowship. M.C. was funded by the European Union (HORIZON-MSCA-2021-PF MOORING, grant agreement no. 101064423). M. R. F.-R. and H. F. M. acknowledge support from the MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR under Grants RYC2021-032167-I and RYC2021-035009-I, respectively. J. C. acknowledges support from the National Science Foundation (Grant OCE-2023161). K. B. W. acknowledges funding provided by the National Science Foundation (Grants OCE-2045399 and OCE-185076) and the U.S. Office of Naval Research (Grant N00014-18-1-2803). Z. Z. acknowledges support from the Moore Foundation and NSF under CAREER Award 1848166Peer reviewe

Genetic Regulation of Platelet Receptor Expression and Function: Application in Clinical Practice and Drug Development

Understanding genetic contributions to platelet function could have profound clinical ramifications for personalizing platelet-directed pharmacotherapy, by providing insight into the risks and possible benefits associated with specific genotypes. This article represents an integrated summary of presentations related to genetic regulation of platelet receptor expression and function given at the Fifth Annual Platelet Colloquium in January 2010. It is supplemented with additional highlights from the literature covering 1) approaches to determining and evidence for the associations of genetic variants with platelet hypo- and hyperresponsive phenotypes, 2) the ramifications of these polymorphisms with regard to clinical responses to antiplatelet therapies, and 3) the role of platelet function/genetic testing in guiding antiplatelet therapy