UTIG - Southeast Caribbean Cruise

Scientific Objective:

We will study the tectonic processes accompanying different stages (past and present) of the Caribbean arc–South America continental collision process,as well as continental growth by collecting geophysical data along transects in the arc-continent collision zone.

The field program will involve land and marine imaging of the crust and mantle beneath the Caribbean Sea.

Locations will include: offshore and onshore Trinidad, offshore and onshore Venezuela, and Tobago

NSF Proposal
Information and Figures

This NSF-sponsored study is a multidisciplinary effort involving scientists from Rice University, UTIG, the University of Arizona, the University of Houston, and Georgia Tech University. Other collaborators include scientists from FUNVISIS (the Venezuelan earthquake studies agency) as well as the Venezuelan and Trinidadian national oil companies.

The study represents one of the most ambitious, integrated studies of arc-continental collisions to date. It will examine how continental growth may be occurring today and in the recent past.
R/V Maurice Ewing Preliminary Cruise Report (PDF, 15MB)
R/V Seward Johnson II Cruise Report (PDF, 20MB)
Click here for a list of talks given while onboard the ship

Q&A on the Southeast Caribbean Project

Why do scientists perform seismic surveys in the oceans?

Geophysical seismic surveying enables geophysicists to "see" the structure of the Earth beneath the surface. The overarching goal of this work is to document the history of the Earth and the processes by which it evolves. This knowledge is vital for understanding climate and sea-level change, Earthquakes and other natural hazards, and the formation and distribution of natural resources.

How do scientists “see” the seafloor and what’s beneath it?

Instead of using light waves reflected off objects to perceive things visually, scientists use acoustic energy waves to "see" deep into the Earth's crust. Unlike light, acoustic energy can travel through seawater and penetrate layers of rock and sediment beneath the Earth’s surface. When acoustic energy waves pass through the Earth they are reflected by some types of rock and sediments and they are bent, or refracted, by others. Devices placed on land, the seafloor or towed by a research ship are used to record the reflected and/or refracted energy from layers of rock and sediment inside the Earth that return to the surface. This returning energy holds a wealth of information about the structure and geology beneath the Earth’s surface.

What will seismologists survey in the Southeast Caribbean?

Funded by the U.S. National Science Foundation, the Southeast Caribbean Continental Dynamics Project is the most ambitious seismologic investigation ever undertaken for basic science in the region encompassing the Leeward Antilles island arc and the Venezuelan coast and mainland. See map here. Oil and gas exploration surveys of the region have concentrated only on the shallowest geologic features, primarily those within the upper four kilometers of the Earth’s surface.

What are the goals of the project?

The Southeast Caribbean region is the source of Earthquakes that have caused devastation in Venezuela and surrounding regions. By investigating the precise location and relationship between fault lines throughout the region, as well as assessing the likelihood of Earthquakes at specific locations, the scientists aim to assess seismic hazards in the Southeast Caribbean region. To aid in this task, the researchers will assemble the most detailed maps ever produced of the large Earthquake-producing faults in Venezuela and the southeast Caribbean Sea.

Geophysicists are also eager to improve their understanding of the tectonics of the Southeast Caribbean plate boundary. The field of tectonics involves the study of the Earth’s crust, specifically the movement of continental plates. Plates are mobile, interconnected regions of the Earth’s surface that move against each other giving rise to mountains, volcanoes, deep ocean trenches, and island arcs. Most Earthquakes are a byproduct of plate motions. At the Southeast Caribbean plate boundary, scientists want to study how continents grow when they collide with plates containing island arcs — like the Leeward Antilles.

What are the seismic hazards in Venezuela?

In its 1999 report, the Global Seismic Hazard Assessment Program, a United Nation’s-endorsed international survey of the world’s Earthquake-prone regions, ranked northern Venezuela as having seismic hazards similar to parts of the San Andreas Fault Region of California. There have been nine Earthquakes of magnitude six or greater in northern Venezuela since 1983, or approximately one large Earthquake every two years. This includes a magnitude 6.9 Earthquake in 1997 that killed 81 people.

How will the Venezuelan people benefit from this study?

The lead Venezuelan partner in the study is Fundacion Venezolana de Investigaciones Sismologicas (FUNVISIS), the Venezuelan national seismological organization. FUNVISIS is the lead Venezuelan agency charged with assessing Earthquake hazards. FUNVISIS will use information from the Southeast Caribbean Project to inform Venezuelan policymakers about ways to improve building codes and otherwise save lives and property in Venezuela.

How will scientists collect their data?

The project involves active and passive seismograph recording, structural geology, basin analysis, and geochemistry. The key experiments are two seismic studies.

In the first, 51 Earthquake recording seismographs in Venezuela and the Caribbean will passively record local, regional, and distant Earthquake sources. This experiment began in autumn 2003 and will run through summer 2005. It makes use of 34 permanently installed broadband instruments in Venezuela that are operated by FUNVISIS, as well as a number of permanently installed high-frequency seismographs.

The second experiment will use approximately 1,475 land-based seismographs, ocean-bottom seismographs and hydrophones to record acoustic signals. This experiment will use reflection and refraction seismology, an active source technique that is similar to the ultrasound medical imaging that produces sonograms of babies in the womb but which uses much lower frequency energy (10-100 Hz). Devices employing compressed air will send out acoustic energy pulses in a manner and level similar to a scuba tank being instantly emptied.