Figure 1. Major physiographic features and active plate boundaries of the Woodlark Basin region. The stippled area encloses oceanic crust formed during the Brunhes Chron at spreading rates labeled in mm/yr. MT and ST = Moresby and Simbo Transform Faults, respectively; DE = D'Entrecasteaux Islands. Top inset: geographical location of the Woodlark Basin. Bottom inset: depth profile along the axis of the spreading center with the five spreading segments numbered.

Figure 2. HAWAII MR1 bathymetric texture and acoustic imagery. Relocated epicenters (black circles) and earthquake focal mechanisms are from Abers et al. (1997). PP = Papuan Peninsula, G = Goodenough Island, F = Fergusson Island, N = Normanby Island, R = Rossel Island, T = Tagula Island, MS = Moresby Seamount, MT = Moresby Transform Fault, M = Misima Island, W = Woodlark Island. The solid line is the landward boundary of oceanic crust, and the dashed line marks the boundary of crust formed during the Brunhes Chron.

Figure 3. Location of the proposed drill sites (Sites ACE-1c, 3c, 7b, 8a, and 9a) and multichannel seismic track data plotted on a base map with 100-m bathymetric contours (thicker contours labeled every km). Relocated earthquake epicenters (open black circles) together with the focal mechanisms (beach balls) are from Abers et al. (1997). The western limit of the Woodlark spreading system is marked by the closed black line, the major rift-bounding normal faults by the ticked lines.

Figure 4. Migrated seismic profiles showing the location of the proposed drill sites, Sites ACE 1c, 3c, 7b, 8a, and 9a.

Figure 5.Nested meridional sections showing the regional and local structures across the incipient conjugate margins. The proposed drill sites are Sites ACE-3c, 8a, and 9a, with alternate Sites ACE-1c and 7b. VE = vertical exaggeration.

Figure 6. Planned reentry cone and casing installation at Site ACE-8a.

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