Borehole Seismic Data


IODP logging contractor: USIO/LDEO

Expedition: 341

Hole: U1421A

Location: Gulf of Alaska

Latitude: 59° 30.4399' N

Longitude: 143°2.7395' W

Logging date: July 27, 2013

Sea floor depth (driller's): 729.7 m DRF

Sea floor depth (logger's): 729 m WRF (DIT/DSI/HLDS/EDTC-B main run)

Total penetration: 702.7 m DSF (1432.4 m DRF)

Core recovery: 20% of cored interval

Oldest sediment recovered: < 0.5 Ma (biostratigraphy)

Lithologies: mud with and without lonestones, diamict, drilled rock, diatom ooze



TOOL USED: VSI (Versatile Seismic Imager)


The logging data was recorded by Schlumberger in LDF format. All processing, including first arrival picking and stacking, was performed by Schlumberger during Expedition 341. The data was then converted into SEGY format at USIO/LDEO, using code developed in house.


Good shots were obtained at six stations (284.7, 467, 531, 570.9, 637, and 687 m WRF).


Stacks are generally calculated with at least nine good traces.

All the data in the SEGY files are sorted shot by shot (i.e. chronologically).


A schematic design of the geometry of the VSI tool is in the Documents section of the hole index page.


Additional information about the drilling and logging operations can be found in the Operations and Downhole Measurements sections of the expedition report, Proceedings of the Integrated Drilling Program, Expedition 341. For further questions about the logs, please contact:


Gilles Guerin

phone: 845-365-8671

fax: 845-365-3182

E-mail: Gilles Guerin


Cristina Broglia

Phone: 845-365-8343

Fax: 845-365-3182

E-mail: Cristina Broglia