Comment on nhess-2021-323

The manuscript presented by Henry et al., can add a substantial contribution to the knowledge of the response of the sediment to moderate earthquakes in a canyon system of a shelf edge in active margins. One of the main findings of this research is obtaining quantitative measurements in real time of the physical parameters (velocity, Ta...etc) of the water and sediment flows generated by earthquakes with magnitude between 4-6. The methodology used is novel and can add significant findings to the understanding of flow dynamic related to currents (turbidity or not) triggered by earthquakes.


GENERAL COMMENTS
The manuscript presented by Henry et al., can add a substantial contribution to the knowledge of the response of the sediment to moderate earthquakes in a canyon system of a shelf edge in active margins. One of the main findings of this research is obtaining quantitative measurements in real time of the physical parameters (velocity, Tª…etc) of the water and sediment flows generated by earthquakes with magnitude between 4-6. The methodology used is novel and can add significant findings to the understanding of flow dynamic related to currents (turbidity or not) triggered by earthquakes.
To really test the value of the flow measurements and main assumptions exposed in the proposed text, it would be very valuable to have sediment cores in that location and check the sedimentological features related to the "events" triggered by the 4.7 and 5.8 earthquakes.
The introduction encompasses the main crucial aspects to be considered for this study and it is properly referenced. However, the focus of the introduction may be slightly changed. Paleoseismic studies are based on the synchroneity of turbidity currents triggered by big earthquakes (> 7 Mw) and their deposits down the canyon confluences in basins with a wide extension (even hundreds of kms) of active margins in an abyssal context. See several works from Adams 1990, Goldfinger (2003, 2006 and Nelson et al. (2000, Gutierrez-Pastor et al., 2013or the Japanese Nakajima et al., 2000and Shiki et al., 2000 Here authors are testing generation of "turbidity currents" triggered by moderate earthquakes in an outlet canyon of the continental shelf edge and their hydrodynamic consequences. From my point of view, I would focus on the study of characteristics of currents triggered by different moderate earthquake magnitudes and think in the possible sceneries (turbidite currents, storms, hyperpycnal flows…etc). I would try to find information in obtained well dated sediment cores in the area and their sedimentological characteristics in relationship with historical earthquakes.
I would separate the discussion from the conclusion. Conclusions may be very clear in a format, preferably, of bullets with the main new insights and findings.
In general, the manuscript is well written although I propose some suggestions in an attempt to improve the content and shape.

SPECIFIC COMMENTS
Lines 37-39: These lines are weakly expressed. I would rephrase them or eliminate in the abstract (maybe include something about it in the introduction, well justified) because here you are comparing small earthquakes recorded just in a proximal site of this margin, with historical big earthquakes (bigger than 7) that trigger turbidites down the canyon confluences in the deep basins.
Lines 57-61: Rephrase this; Actually, seismoturbidites deposit over the hemipelagic sediment below, that represent a quiet open ocean environment. In the way that is expressed look like the hemipelagic is overlying the sandy/turbidite base?? You may specify that the "layer of apparently homogenous mud with small or gradual, if any, variations in grain size and chemical composition" may correspond to the tail of the turbidite. There is a Lines 93-97: As said in a comment above, be careful with comparing seismoturbidites triggered by big earthquakes and recorded in the sediment in wide margin areas with this local turbidite flows measured with an artifact locally. You could focus the study in showing the characteristics of the flows and sediment involved in the triggered current to improve the understanding of turbidite currents generated by earthquakes in proximal sites. This is very valuable to understand the hydrodynamic conditions during and at the time of the deposition, and compare with other records (such as storms, hyperpycnal flows…etc).
Line 114-116: This is extra, eliminate it: "that differ…etc" Lines 270-281: The beginning of Section 3.2 is not easy to follow. It is very confusing. You state "main earthquake" (Do you mean the one of Mw 5.8?), "During that event" or during "all three events". You may specify better and express it in a way more under stable.
Lines 381-383: This assumption seems to contradict lines 366 and 367, where you state that speed of less than 4 cm/s may have been insufficient to put particles in suspension. However, here you say that several turbid events are observed.
Line 389: specified the seasonal temperature variability ranges, if possible Line 422: In this section I miss any table explaining the sequence of events or even a drawing. I suggest to add any table, scheme or draft to improve and clarify the meaning of the events.
Lines 499-501: You should mention here that a sedimentary record would complement the hydrodynamic interpretations and would support your work. Consider that If there is any sediment core in the area that is well dated, you could look for the historical earthquakes of magnitudes between 4-6 and have a look to the sediment corresponding to the date of that historical earthquake. So, you could test if there is turbidites and their characteristics, as you describe from your observations. To me, this is the most interesting point that can add (really) to the Paleoseismology, in relationship with moderate earthquakes in proximal settings. Line 449: Here you define "seiche". Revise in the text where it appears for first time and define it there.
Lines 489-491: add a verb "how earthquakes scale influences the hydrodynamic Line 533: "observatory", Do you mean the instrument?
Line 544: Include "that". The scenario that we propose…