A submarine mud volcano eruption triggered a 100 m thick mass flow

Offshore mud volcanoes can be sites of energetic eruptions and flank collapse. Using three dimensional seismic data from the Gulf of Mexico, we reveal an extensive mass flow (>1.1 × 10 9 m 3 ) that is linked to one of the region's largest and active mud volcanoes, the Kohl mud volcano. Our analysis reveals a collapsed southeastern crater flank that is ~1300 m wide and marked by collapse scarps at Kohl. The resulting mass flow is characterized by basin-verging (~16°) toe thrusts, widens downslope, and ends abruptly at a moat on the seafloor. Unlike typical thin, less cohesive mud volcano flows, this deposit is ~100 m thick, extends ~6000 m downslope, and originates from the failed southeastern rim. The deposit is bound by kilometer-scale faults that connect the collapse scarp upslope at the mud volcano crater, and exhibits localized erosion below its debris tongue, typical of mass transport deposits. Erosive and compressional behaviors define the terminal phase of the mass flow emplacement and likely reflect an energetic emplacement event. We argue that an energetic eruption and subsequent crater rim and flank collapse provides the most plausible explanation for our observations, highlighting the feedback between submarine mud volcanism and mass wasting. This study represents an important step forward for understanding how submarine mud volcanism influences the formation of thick and erosive mass flows and the processes that govern the emplacement of such flows on seafloors globally. • Analysis of marine seismic data reveals a 100 m thick mud volcano-related mass flow. • We infer that an energetic eruption triggered the collapse of mud volcano crater flank and mass flow with a runout distance of 6000 m. • Erosive flow and compressional deformation are likely to be common processes during submarine mud volcano flank collapse emplacement.