Collaborative Research: Interactions Between Transpressional Structures at the North American-Caribbean Plate Boundary: Geophysical Imaging Beneath Lake Azuei, Haiti

GSTDTAP

项目编号	1624556
	Collaborative Research: Interactions Between Transpressional Structures at the North American-Caribbean Plate Boundary: Geophysical Imaging Beneath Lake Azuei, Haiti
	Heather Sloan
主持机构	CUNY Herbert H. Lehman College
项目开始年	2016
	2016-11-01
项目结束日期	2019-10-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	136072(USD)
国家	美国
语种	英语
英文摘要	Motion along plate boundaries where two plates collide, such as subduction or continental collision zones, is typically head-on. In some cases, the collisions are more oblique, a situation that sets up a complex pattern of crustal deformation. Some deformation is accommodated by faults that allow crustal blocks to slide by each other and some deformation is accommodated by development of folds and faults with both a vertical and horizontal component of motion. The boundary between the Caribbean and North American plates is such a case. A research team of scientists from the University of Rhode Island, City University of New York, and University d'Etat de Haiti is carrying out a seismic reflection and sediment coring study on Lake Azuei, Haiti, in order determine how the faults in this region are moving in response to oblique plate collision. This region is of particular interest because the study area lies just to the east of the rupture zone of the January 12, 2010 magnitude 7.0 Haiti earthquake, the catastrophic event that devastated the capital Port-au-Prince and surrounding regions. In addition to shedding light on how motion along this plate boundary is accommodated, this study will provide some critical information needed for a meaningful assessment of the seismic hazards facing this densely populated region. The project will advance other desired societal outcomes through: involvement of education major students in the project; development of a diverse, globally competitive STEM workforce through graduate and undergraduate student training; and close collaboration with Haitian scientists. To a first order, the Caribbean plate is moving east-northeastward at about 2 cm/yr relative to the North American plate, implying an oblique convergence between the two plates. This oblique convergence is partly accommodated across the island of Hispaniola by the partitioning of motion between two east-west left-lateral transform faults and a fold-and-thrust belt that strikes northwest-southeast. Surprisingly, the 2010 Mw7.0 Haiti earthquake did not rupture along the well-defined trace of the Enriquillo-Plantain Garden Fault, the southern transform fault. Instead, slip occurred on an unsuspected blind oblique thrust fault that abuts the strike-slip fault. Similar hazardous interactions between strike-slip and thrust faults are expected elsewhere along Hispaniola. In particular, Lake Azuei, located about 30 km east of Haiti's capital city of Port-au-Prince, is bisected by the Enriquillo-Plantain Garden Fault and is bounded to the north and east by the Haiti fold-and-thrust belt. This project employs a high-resolution multichannel seismic reflection survey and CHIRP sub-bottom profiling to image both strike-slip and thrust-fold structures where they meet beneath Lake Azuei and will determine the spatial and temporal relations between them. Lake Azuei, a shallow lake located about 60 km east of the 2010 epicenter, is crossed by the Enriquillo-Plantain Garden Fault and is also bounded by the Haiti fold-and-thrust belt. A two-week survey will produce a dense grid of high-resolution multichannel seismic reflection profiles with an expected penetration of at least a few hundred meters below the lake bed. CHIRP subbottom profiles will be acquired concurrently; these will provide an even higher stratigraphic resolution (sub-meter) but with a lower penetration (up to 20 m). In addition, the seismic stratigraphy will be ground-truthed with a series of short sediment cores. These cores will be sited where seismic data indicate that deeper (older) seismic horizons intersect the lake bed. Sediment samples will be dated using a combination of paleomagnetic measurements and radioisotopic methods in order to establish a Holocene chronostratigraphy for Lake Azuei. The careful stratigraphic analysis of the seismic reflection and CHIRP profiles will result in a digital representation of faults, folds, and sequence boundaries in three-dimensions. Together with the stratigraphic analysis of the sediment cores, this project will thus characterize the spatial and temporal relations between the two sets of oblique structures.
来源学科分类	Geosciences - Earth Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/70565
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Heather Sloan.Collaborative Research: Interactions Between Transpressional Structures at the North American-Caribbean Plate Boundary: Geophysical Imaging Beneath Lake Azuei, Haiti.2016.