Hawaii Mapping Research Group

The Hawaii Mapping Research Group (HMRG) is a research and operational group within University of Hawaii’s School of Ocean and Earth Science and Technology (SOEST) and the Hawaii Institute of Geophysics and Planetology (HIGP), that has specialized in seafloor mapping technology development and mapping services for over 25 years.

HMRG’s Family of Towed Sonar Systems

HMRG currently maintains and operates three towed bathymetric sidescan sonar systems that provide a wide range of mapping capabilities: MR1, IMI120, and IMI30. Additional oceanographic sensors, including magnetometers, subbottom profilers, motion sensors, sound velocity profilers, and CTDS, are or can be deployed as part of the instrument packages.

MR1 Towed Sonar

The MR1 is a shallow-towed 11/12-kHz bathymetric sidescan sonar developed and operated by HMRG. The MR1 provides full ocean depth capabilities, both bathymetry and sidescan data, and broad coverage and has been deployed on over 30 cruises since 1990.

IMI120 Towed Sonar

The IMI120 is a deep-towed 120-kHz bathymetric sidescan sonar originally developed by
Woods Hole Oceanographic Institute as the DSL-120, subsequently rebuilt as the DSL-120A with an HMRG-engineered mapping sonar, and jointly operated by WHOI and HMRG for several years. Now named IMI120 (IMI means “Seeker” in Hawaiian) and operated by HMRG, this instrument provides high-resolution sidescan and phase-difference bathymetry for detailed analysis of seafloor features and is towed 50-100 m above the seafloor.

IMI30 Towed Sonar

The IMI30 is a 30-kHz bathymetric sidescan sonar developed and operated by HMRG. At 30 kHz, IMI30 produces higher resolution data than the MR1, but broader coverage than the IMI120 and is towed several hundred meters above the seafloor.

Multibeam Support

HMRG mapping personnel work closely with SOEST’s Ocean Technology Group (OTG) and the Hawaii Undersea Research Laboratory (HURL) in testing, calibration, and operation of SOEST’s multibeam sonars. The R/V Kilo Moana has both deep and shallow mapping capabilities with Kongsberg 12-kHz EM122 and a 70-100 kHz EM710 multibeam sonars. The R/V Ka’imikai-O-Kanaloa is equipped with a 12-kHz Seabeam 3012 multibeam.


HMRG provides data collection, processing and archiving services for towed sidescan and multibeam surveys. Two mapping data archives are currently available on-line at HMRG:

The Main Hawaiian Island Bathymetric Data Synthesis

MR1 Archive

Cruise Planning

Advance information is vital to planning a successful cruise, particularly when deploying large and complex oceanographic equipment. Information on HMRG shipboard operations, support vessel requirements, personnel requirements; data collection and processing policies and products are provided.