Application for Consent to Conduct Marine Scientific Research

Transcripción

1 1. General Information Application for Consent to Conduct Marine Scientific Research 1.1 Reference ID: Application number: Project name: F Melville 2012 Trehu 1.2 Sponsoring institution(s): Institution Contact Information Director National Science Foundation Division of Ocean Sciences (GEO/OCE) 4201 Wilson Boulevard Arlington, VA Scientist in charge of the project: Anne Trehu Affiliation: Oregon State University Address: College of Oceanic Atmospheric Sciences Apt/Suite: 104 COAS Admin Building Phone: Scientists from coastal states involved in the planning of the project: See Section 8 (Participation) 1.5 Submitting officer: Elizabeth Brenner Affiliation: Scripps Institution of Oceanography Address: 9500 Gilman Drive Phone: Fax: shipsked@ucsd.edu 2. Description of Project 2.1 Nature and objectives of the project: Dr. David O. Conover Collaborative Research: Post-seismic response updip of the Chilean megathrust earthquake of February 27, The primary objective of this project is to deploy a focused array of 10 broadband ocean bottom seismometers outfitted with SIO seafloor flow meters up-dip of the region of maximum slip during the Maule, Chile, earthquake of Feb. 27, 2010 to monitor the post-seismic response of the outer accretionary prism. Onshore and offshore seismological data suggest that slip during the main event and in the immediate aftershock period stopped ~30 km down-dip of the trench. The lack of a detectable bathymetric change in the outer accretionary complex a month after the earthquake also suggests that the upper part of the megathrust did not slip during the event. Based on these observations, we expect that the outer accretionary wedge behaves as a poroelastic medium and adjusts gradually, through multiple faults, folds and volumetric strain, to the change in stress resulting from up to 20 m of slip on the megathrust during the earthquake. Although the downdip edge of the seismogenic zone of megathrust faults has been instrumented in many regions, very few data are available from the updip edge of the seismogenic zone, which is almost always offshore. The close spacing (~10 km) of our planned array on the lower slope in water depths of m immediately seaward of the patch of greatest slip during the earthquake should allow us to study a wide range of seismic and hydrological responses that should be occurring as the accretionary complex adjusts to the change in stress caused by the earthquake. In particular, we will look for seismic tremor and for low frequency earthquakes as well as for normal earthquakes in the prism and underlying subducting crust and for slow fluid flow out of the seafloor that can be modeled to derive volumetric strain in the underlying sediments. High-resolution seismic and bathymetric data will also be acquired over the instrument sites during the deployment cruise. These data will be used to: (1) orient the horizontal components of the OBSs; (2) map faults, folds and stratigraphic horizons that may be accommodating deformation and acting as fluid conduits, 1 of 5 10/24/11 10:31 AM

2 (3) estimate heat flow through its seismic proxy, a bottom simulating reflection that marks the base of the gas hydrate stability field, and (4) provide a framework for instruction for a cohort of students who will also participate as watchstanders. (espanol) El principal objetivo de este projecto es el de instalar un grupo de 10 sismometros de fondo integrados a medidores de flujo del Instituto de Oceanografia de Scripps, en la region de maximo deslace durante el terremoto de Maule, Chile el 27 de Febrero, El proposito es el de estudiar el comportamiento post-sismico del area. Datos sismologicos obtenidos sugieren que el desplazamiento durante el evento principal se extendio a 30 km de la trencha. Datos batimetricos indicant que la parte superior de la falla no se desplazo durante el evento. Estas observaciones sugieren que el prisma de accrecion distal se comporta como un medio poroelastico que se ajusta gradualmente, a traves de multiples fallas, al cambio que resulta de los 20 m de desplazamiento durante el terremoto. Nuestro plan es el de instalar intrumentos cada 10 km en una red que se instalara a una profundidad de 2000 a m, que corresponde a la zona que se encuentra en la vecinidad del area de major desplazamiento durante el terremoto. Este equipo nos permitira estudiar las respuestas sismicas y hydrogeologicas que estan occurrendo mientras el complejo de acrecion se ajusta al desplazamiento sostenedo por el terremoto. Especialmente, la red propuesta servira para construer un record de de temblores y sismos de baja frequencia y sismos normales el el prisma de accrecion y en las placas de subduccion. Flujo de fluids que se medira en el suelo marino podra ser utilizado para complementar los modelos sismo-hydraulicos. Estos datos seran usados para: (1) oreintar los components horizontals del OBS, (2) mapear fallas, y horizontes estratigraficos que puedan acomodar la dfeformacion y que actuen como conductos para migracion de flujos, (3) estimar el flujo termico basado en modelos de estabilidad de hydratos de metano y reflectores sismicos caracteristicos, y (4) proveer instruccion a un grupo de estudiantes que participara en el experimento. 2.2 Relevant previous or future research projects: Trehu - previous research in this region. 2 decades of research on seismic imaging of the Cascadia forearc. (espanol) investigaciones previas en esta zona. Dos decadas de investigaciones de sismologia en el margen de Cascadia. Tryon - NSF RAPID bathymetric survey of the Chilean forearc in 2010 to detect whether there were any changes in the seafloor after the Maule earthquake. 15 years of research on fluid flow in other forearcs. (espanol) Participo en un studio batimetrico de la costa de Chile en 2010 para detectar cambios en el suelo marino despues del terremoto de 2010, financiado por NSF. Quince anos de experiencia en flujo de fluidos en varias localidades marinas. 2.3 Previously published research data relating to project: publications specific to the Chilean margin. Some related references include: (espanol) hay publicaciones especificas al margen de Chile. Otras publicaciones relacionadas al tema son: Tréhu, A.M., R. Blakely, and M.C. Williams, Subducted seamounts and recent earthquakes beneath the central Cascadia margin, Geology, in press. Tréhu, A.M., Braunmiller, J., Nabelek, J.L., Probable low-angle thrust earthquakes on the Juan de Fuca-rth America plate boundary, 2008, Geology, v. 36, p Tréhu, A.M., and E. Flueh, Estimating the thickness of the free gas zone beneath Hydrate Ridge, Oregon continental margin, from seismic velocities and attenuation, Jour. Geophys. Res., v. 106, p , Tréhu, A.M., D.S. Stakes, C.D. Bartlett, J. Chevallier, R.A. Duncan, S.K. Goffredi, S.M. Potter, K.A. Salamy, Seismic and seafloor evidence for free gas, gas hydrates, and fluid seeps on the transform margin offshore Cape Mendocino, J. Geophys. Res., 108, 2263 (19 pp.), doi: /2001jb001679, Tryon, M.D., Monitoring aseismic tectonic processes via hydrologic responses: an analysis of log-periodic fluid flow events at the Costa Rica outer rise, Geology, v. 37, p , Tryon, M. D., and K. M. Brown, Observations of hydrotectonic stress/strain events at a basement high at the Nicoya outer rise, Eos Trans. AGU, 86(52), T33A-0516, Tryon, M. D., K. M. Brown, L. M. Dorman, and A. Sauter, A new benthic aqueous flux meter for very low to moderate discharge rates, Deep-Sea Res. I, 48(9), , Methods and Means to be Used 3.1 Platform: MELVILLE Nationality (Flag State): United States Overall length: Maximum draught (meters): Displacement/gross tonnage: Propulsion: Two 1385 hp Z-Drive Lips Call sign: WECB Cruising speed: Maximum speed: of 5 10/24/11 10:31 AM

3 Name of captain/master: Christopher Curl Number of crew: 23 Number of scientists on board: Other craft used in the project: n.a 3.3 Methods and scientific instruments: Types of Samples and Data Methods to be Used Instruments to be Used Digital time series recovered when the instruments are recovered. ******** Series de tiempo digitales seran obtenidas al recobrar los instrumentos. Digital time series acquired on the vessel. ******** Series de tiempo digitales seran obtenidas a bordo. Underway (UW) multibeam and single beam****** Multihaz y rayo individual en transito Meteorological variables (e.g. wind speed, heat flux, air temperature, waves, etc)************ Meteorológica variables (por ejemplo, la velocidad del viento, flujo de calor, tempertature de aire, onda, etc) UW Mags if available************* Ejecucio n magne tica encuestas en marcha si es disponible UW Gravity if available**** Gravimetrica en marcha si es disponible 3.4 Will harmful substances be used? 3.5 Will drilling be carried out? 3.6 Will explosives be used? 3.7 Will protected species be studied? 4. Installations and Equipment 4.1 Will there be any installations? Natural source seismology and hydrogeology. ******** Sismologia e hydrologia de fuentes naturale. High-resolution seismic reflection. ******** Refleccion sismica de alta resolucion. Swath mapping Sub-Bottom Profiler*****Cartografía y Sub Profiler Ship-based surveys**********enquesta sobre el buque Magnetometer deployment***********despliegue de magneto metro Gravity collection******* Coleccion de gravedad Ocean-bottom seismometers with integrated flow meters. 100 m long multichannel hydrophone streamer; Generator/injector-type airgun. M120 multibeam, 12khz and Knudsen 320 B 3.5 / 12 Shipboard meteorological sensors**********sensores meteorológicos a bordo el buque Marine Magnetics total field gradiometer Bell Gravimeter yes Ten ocean bottom seismometers with integrated flow meters will be deployed at the following sites. Instruments will be recovered approximately one year later. (espanol) Diez seismometros de fondo y 3 of 5 10/24/11 10:31 AM

4 medidores de flujo integrados seran instalados en los siguentes lugares. Los instrumentos seran recobrados aproximadamente un ano mas tarde. Name Latitude Longitude Depth (m) OBS OBS OBS OBS OBS OBS OBS OBS OBS OBS Geographical Area(s) 6. Dates 5.1 Indicate geographical areas in which the project is to be conducted (with reference in latitude and longitude): 34.18S, 73.62W to 34.78S, 72.42W 5.2 Attach chart(s) showing the geographical areas of the intended work and, as far as practicable, the positions of intended stations, the tracks of survey lines, and the locations of installations and equipment: See Section 10 (Attachments) 6.1 Expected dates: 7. Port Call(s) Project Start Date: Apr 20, 2012 Project End Date: May 19, 2012 Coastal Area Estimated Entry Date Estimated Departure Date Chile Apr 20, 2012 May 15, 2012 Explanation of multiple entries: N/A Research will be performed: between nm Multiple Entries Expected? Extent to which Chile will be enabled to participate or to be represented in the research project: Up to 6 bunks will be available for faculty and students from Chile. Total number who will participate will depend on whether additional funds are raised to support travel. (espanol) Un maximo de 6 espacios se reservaran para sicnetificos y estudiantes chilenos. El numero de participanted de Chile dependera de los fondos adicionales necesarios para cubrir gastos de viaje. Port Arrival Date End Date Punta Arenas 4/21/2012 4/24/2012 Valparaiso 5/12/2012 5/16/2012 Special Logistical Requirements fueling re-provisioning. Fueling and re-provisioning. Shipping Agent Agent: A.J. Broom y Cia S.A.C Physical Address Errazuriz 629 3er. Piso, Valparaiso Chile Tel: Fax: Web: POC : Mario Montero / Operations Manager Broom Group Agent: A.J. Broom y Cia S.A.C Physical Address Errazuriz 629 3er. Piso, Valparaiso Chile Tel: Fax: Web: POC : Mario Montero / 4 of 5 10/24/11 10:31 AM

5 Operations Manager Broom Group 8. Participation 8.1 Extent to which coastal state(s) will be able to participate or to be represented in the research project: See Section 6 (Dates) 8.2 Proposal dates and ports for embarkation/disembarkation: See Section 7 (Port Call(s)) 9. Access to Data, Samples and Research Results 9.1 Expected dates of submission to coastal State of preliminary reports, which should include the expected dates of submission of the final results: more than 30 days from the end date of the research. 9.2 Propose means for access by coastal state to data and samples: Data will be provided through official channels at no cost to the coastal State(s). Samples will be provided upon request. 9.3 Propose means to provide coastal State with assessment of data, samples and research results or provide assistance in their assessment or interpretation: Assessment of data, samples, and research results will be provided at no cost to the coastal State(s). Assistance in futher assessment or interpretation will be provided upon request. 9.4 Propose means of making results internationally available: Results will be published in peer-reviewed journals. After an initial proprietary period, OBS data will be deposited in the publicly accessible IRIS data base. (espanol) Los resultados seran publicados en revistas cientificas. Despues de un periodo propietario, los datos del OBS seran depositados en el bacon de datos IRIS para accesso publico. 10. Attachment(s) Additional Attachments Attachment Type Description Attachment Submission Date Proposed Cruise Track Map showing planned OBS deployment sites (circles) and track lines for high-resolution seismic reflection (red lines) _map.jpg 5 of 5 10/24/11 10:31 AM