Description: Between 08.08.2003 and 02.09.2003, bathymetric data was acquired offshore Guatemala and Costa Rica during the R/V SONNE cruise SO173/2. The expedition comprised geophysical and biological research objectives. One aim was the acquisition of geophysical data for a better understanding of recent and long-term evolution of the Middle America Landbridge and mass flux into the subduction system. Moreover, the cruise was also dedicated to studying the sensory systems of mesopelagic fish, cephalopods, crustaceans and teleosts by using trawl gear and morphometric studies. Bathymetric mapping with the multibeam echosounder (MBES) SIMRAD EM120 was utilized to obtain a full coverage bathymetric map along the El Salvador and Guatemalan continental slope and to complete previous maps by filling gaps along the continental slope and oceanic plate of Nicaragua. Further geophysical instruments, such as the sub-bottom profiler PARASOUND, magnetometer, a dredge and seismic instrumentation, and biological equipment including trawling gear and lab instrumentation, complemented the research equipment. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the SO173/2 cruise, the hull-mounted multibeam echosounder (MBES) SIMRAD EM120 was utilized to perform bathymetric mapping. It allows to conduct surveys in water depths of up to 11,000 m. Two transducer arrays transmit successive frequency coded acoustic signals (11.25 to 12.6 kHz). Data acquisition is based on successive emission-reception cycles of the signal. While the emission beam has a dimension of 150° across and 2° along track, the reception is obtained from 191 overlapping beams with widths of 2° across and 20° along track. The beam footprint has a dimension of 2° by 2°. The beam spacing can be set to equidistant or equiangular. For further information on the system, consult: https://www.km.kongsberg.com/ Depth is estimated from each beam by using the two-way travel time and the beam angle known from each beam, and taking into account the ray bending due to refraction in the water column by sound speed variations. Combining phase and amplitude is used to provide measurement accuracy practically independent of the beam pointing angle. During the SO173 cruise, the EM120 was used continuously. At the beginning of the cruise, a sound velocity profile was measured to a depth of 2000 m. Responsible person during this cruise / PI: Wilhelm Weinrebe (wweinrebe@ifm-geomar.de) Chief Scientist: Wilhelm Weinrebe (wweinrebe@ifm-geomar.de) CR: http://oceanrep.geomar.de/13407/1/Geomar-Report-116.pdf CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2003/20040060.htm This dataset was published as part of: Geersen, Jacob (2019): Collated bathymetric data from convergent margins that experienced tsunami earthquakes. PANGAEA, https://doi.org/10.1594/PANGAEA.899049