Presentation Title

LiDAR Mapping of Earthquake Uplifted Paleo-shorelines, Southern Wairarapa Coast, North Island, New Zealand

Faculty Mentor

Jeffrey S. Marshall

Start Date

18-11-2017 2:15 PM

End Date

18-11-2017 3:15 PM

Location

BSC-Ursa Minor 26

Session

Poster 3

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

The Hikurangi subduction margin along the east coast of the North Island, New Zealand accommodates oblique convergence of the Pacific Plate westward beneath the Australian plate at 45 mm/yr. Pronounced forearc uplift occurs at the southern end of the margin along the Wairarapa coast, onshore of the subducting Hikurangi plateau. Uplifted flights of Holocene marine terraces and associated beach ridges provide a paleo-seismic record of past coseismic uplift events.

In January 2017, we participated in the Research Experience for Undergraduates (REU) program of the NSF SHIRE Project (Subduction at Hikurangi Integrated Research Experiment). For the coastline between Flat Point and Te Kaukau Point, we used airborne LiDAR data provided by Land Information New Zealand (LINZ) to create ArcGIS digital terrain models for mapping and correlating uplifted paleo-shorelines. Prior field mapping and radiocarbon dating results (Berryman et al., 2001; Litchfield and Clark, 2015) were used to guide our efforts. The resultant maps show between four and seven uplifted terraces and associated beach ridges along this coastal segment. At some sites, mapping efforts are impeded by discontinuous exposures and the presence of landslide debris, alluvial fan deposits, and sand dunes.

Tectonic uplift along the southern Hikurangi margin is generated by a complex interaction between deep megathrust slip and shallow upper-plate faulting. Each uplifted Holocene paleo-shoreline is interpreted to represent a single uplift event. Continued research may help differentiate between very large megathrust earthquakes (M8.0-9.0+) and smaller, more localized upper-plate thrust events (M7.0-8.0).

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Nov 18th, 2:15 PM Nov 18th, 3:15 PM

LiDAR Mapping of Earthquake Uplifted Paleo-shorelines, Southern Wairarapa Coast, North Island, New Zealand

BSC-Ursa Minor 26

The Hikurangi subduction margin along the east coast of the North Island, New Zealand accommodates oblique convergence of the Pacific Plate westward beneath the Australian plate at 45 mm/yr. Pronounced forearc uplift occurs at the southern end of the margin along the Wairarapa coast, onshore of the subducting Hikurangi plateau. Uplifted flights of Holocene marine terraces and associated beach ridges provide a paleo-seismic record of past coseismic uplift events.

In January 2017, we participated in the Research Experience for Undergraduates (REU) program of the NSF SHIRE Project (Subduction at Hikurangi Integrated Research Experiment). For the coastline between Flat Point and Te Kaukau Point, we used airborne LiDAR data provided by Land Information New Zealand (LINZ) to create ArcGIS digital terrain models for mapping and correlating uplifted paleo-shorelines. Prior field mapping and radiocarbon dating results (Berryman et al., 2001; Litchfield and Clark, 2015) were used to guide our efforts. The resultant maps show between four and seven uplifted terraces and associated beach ridges along this coastal segment. At some sites, mapping efforts are impeded by discontinuous exposures and the presence of landslide debris, alluvial fan deposits, and sand dunes.

Tectonic uplift along the southern Hikurangi margin is generated by a complex interaction between deep megathrust slip and shallow upper-plate faulting. Each uplifted Holocene paleo-shoreline is interpreted to represent a single uplift event. Continued research may help differentiate between very large megathrust earthquakes (M8.0-9.0+) and smaller, more localized upper-plate thrust events (M7.0-8.0).