Submarine landslide as the source for the October 11, 1918 Mona Passage tsunami : observations and modeling

This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 254 (2008): 35-46, doi:10.1016/j.margeo.2008.05.001.The October 11, 1918 ML 7.5 earthquake in the Mona Passage between Hispaniola and Puerto Rico generated a local tsunami that claimed approximately 100 lives along the western coast of Puerto Rico. The area affected by this tsunami is now significantly more populated. Newly acquired high-resolution bathymetry and seismic reflection lines in the Mona Passage show a fresh submarine landslide 15 km northwest of Rinćon in northwestern Puerto Rico and in the vicinity of the first published earthquake epicenter. The landslide area is approximately 76 km2 and probably displaced a total volume of 10 km3. The landslide's headscarp is at a water depth of 1200 m, with the debris flow extending to a water depth of 4200 m. Submarine telegraph cables were reported cut by a landslide in this area following the earthquake, further suggesting that the landslide was the result of the October 11, 1918 earthquake. On the other hand, the location of the previously suggested source of the 1918 tsunami, a normal fault along the east wall of Mona Rift, does not show recent seafloor rupture. Using the extended, weakly non-linear hydrodynamic equations implemented in the program COULWAVE, we modeled the tsunami as generated by a landslide with a duration of 325 s (corresponding to an average speed of ~ 27 m/s) and with the observed dimensions and location. Calculated marigrams show a leading depression wave followed by a maximum positive amplitude in agreement with the reported polarity, relative amplitudes, and arrival times. Our results suggest this newly-identified landslide, which was likely triggered by the 1918 earthquake, was the primary cause of the October 11, 1918 tsunami and not the earthquake itself. Results from this study should be useful to help discern poorly constrained tsunami sources in other case studies

Morphotectonics of the central Muertos thrust belt and Muertos Trough (northeastern Caribbean)

Multibeam bathymetry data acquired during the 2005 Spanish R/V Hespérides cruise and reprocessed multichannel seismic profiles provide the basis for the analysis of the morphology and deformation in the central Muertos Trough and Muertos thrust belt. The Muertos Trough is an elongated basin developed where the Venezuelan Basin crust is thrusted under the Muertos fold-and-thrust belt. Structural variations along the Muertos Trough are suggested to be a consequence of the overburden of the asymmetrical thrust belt and by the variable nature of the Venezuelan Basin crust along the margin. The insular slope can be divided into three east–west trending slope provinces with high lateral variability which correspond to different accretion stages: 1) The lower slope is composed of an active sequence of imbricate thrust slices and closed fold axes, which form short and narrow accretionary ridges and elongated slope basins; 2) The middle slope shows a less active imbricate structure resulting in lower superficial deformation and bigger slope basins; 3) The upper slope comprises the talus region and extended terraces burying an island arc basement and an inactive imbricate structure. The talus region is characterized by a dense drainage network that transports turbidite flows from the islands and their surrounding carbonate platform areas to the slope basins and sometimes to the trough. In the survey area the accommodation of the ongoing east–west differential motion between the Hispaniola and the Puerto Rico–Virgin Islands blocks takes place by means of diffuse deformation. The asymmetrical development of the thrust belt is not related to the geological conditions in the foreland, but rather may be caused by variations in the geometry and movement of the backstop. The map-view curves of the thrust belt and the symmetry of the recesses suggest a main north–south convergence along the Muertos margin. The western end of the Investigator Fault Zone comprises a broad band of active normal faults which result in high instability of the upper insular slope

The identification of a low molecular mass bacteriocin, rhamnosin A, produced by Lactobacillus rhamnosus strain 68

Aims: This study focuses on the isolation and characterization of a peptide with bacteriocin-like properties isolated from Lactobacillus rhamnosus strain 68, previously identified by 16S rRNA gene sequencing and originating from human gastrointestinal flora. Methods and Results: The peptide was isolated from a supernatant of bacteria maintained under restrictive conditions by a combination of ethanol precipitation and reversed-phase chromatography. The molecular mass of the peptide as assessed by mass spectrometry was 6433 center dot 8 Da. An isoelectric point of 9 center dot 8 was determined by 2D-PAGE. The peptide designated rhamnosin A inhibited Micrococcus lysodeikticus ATCC 4698 but did not inhibit Lactobacillus plantarum 8014 or Lact. plantarum 39268. Inhibitory activity against M. lysodeikticus at concentrations used in this study was shown to be bacteriostatic rather than bacteriolytic or bactericidal. Rhamnosin A retained biological activity after heat treatment (95 degrees C, 30 min) but was sensitive to proteolytic activity of pepsin and trypsin. Conclusions: The N-terminal sequence of rhamnosin A, as determined by Edman degradation and in more detail by blast analysis, did not show identity with any currently available Lact. rhamnosus HN001-translated protein sequences, nor any significant similarity with other sequences in the nonredundant protein sequence database. Being a small, heat-stable, nonlanthionine-containing peptide, rhamnosin A should be categorized as a class II bacteriocin. Significance and Impact of the Study: This study describes a partial bacteriocin sequence isolated from Lact. rhamnosus 68 and broadens our understanding of bacteriocins

Biomarkers of Nutrition for Development (BOND)—Iron Review

This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health. The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation

Bathymetric Terrain Model of the Atlantic Margin for Marine Geological Investigations Open-File Report 2012-1266

For more information on the USGS-the Federal source for science about the Earth, it's natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein.ny use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. iii Acknowledgements This report was prepared as part of a multiyear project funded by the NRC to study potential effects of tsunamis produced from marine landslides. We thank the Captain and crew of the NOAA Ship Okeanos Explorer for their recent mapping efforts along the Atlantic margin. William Danforth and Richard Signell of the USGS provided helpful comments. We thank VeeAnn Cross of the USGS for her comments on the metadata, Andrea Toran for her expertise in Web design, and Anna Glover for her editorial review of this report. Abstract Bathymetric terrain models of seafloor morphology are an important component of marine geological investigations. Advances in acquisition and processing technologies of bathymetric data have facilitated the creation of high-resolution bathymetric surfaces that approach the resolution of similar surfaces available for onshore investigations. These bathymetric terrain models provide a detailed representation of the Earth's subaqueous surface and, when combined with other geophysical and geological datasets, allow for interpretation of modern and ancient geological processes. The purpose of the bathymetric terrain model presented in this report is to provide a high-quality bathymetric surface of the Atlantic margin of the United States that can be used to augment current and future marine geological investigations. The input data for this bathymetric terrain model, covering almost 305,000 square kilometers, were acquired by several sources, including the U.S