Von daher ist es egal, ob der Typ im OP deutsch klingt oder nicht.

Sicher ist es im Grunde egal. In meinen Ohren klingt er für jemanden, der erst im Erwachsenenalter in die USA übersiedelt ist (Hintergrundwissen) überraschend "echt amerikanisch". Es interessiert mich deshalb einfach, wie insbesondere Muttersprachler so jemanden instinktiv einordnen. Bisher hat sich leider noch keiner geäußert.

AE here. This is not a native USA accent.

It is a Germanic accent for sure. North Germanic (Scandinavia), Dutch(Niederländisch), or German probably. All of the Germanic dialects of non-native English speakers sound similar to us native speakers.

I jumped around the video listening for errors or just imperfect speech.

1:03: "A little bit on <??????>". Closed Captioning hilariously interprets this as "diversity". Maybe he's saying "induced seismicity", but I'm not sure.

1:15: Weak 't', sounds too close to "fall" and "falls". The 't' is there, however. I know he's saying "fault" because earthquakes happen on "fault lines" or "faults", and the subject of the slide is "seismology" (study of earthquakes).

1:24: "Might induce ground" --> "Might induce grount"

5:22: "So we" --> "So vie"

9:40: "We inject for about 150 days". Present tense sounds unnatural.

12:31: "I don't read them to you" Present tense :( Should be "I won't read them to you" or "I won't be reading them to you" or "I don't need to read them for you".

Many non-native English speakers don't use the right pattern when speaking. "Sentence stress" or "rhythm" are terms I see for this. There are patterns of syllable stress in a sentence. When this pattern is really terrible, then we can't understand the sentences. The speaker's pattern is close, but not perfect.

Summary:

This is not a "native accent". It is quite understandable, however. Feels very Germanic, but it isn't bad. The accent is less noticeable later in the video. 7 out of 10?

Mir fiel direkt am Anfang auf, dass er viel der amerikanischen Aussprache übernommen hat, das aber nicht durchzieht. Beer mit viel Zeit auf dem r-Laut, aber direkt davor hard mit völlig deutschem Akzent.

und eine hielt mich sogar für einen Australier! (#4)

Wow – no worries!

People here have thought I might be Dutch or Swiss.

Mir fiel direkt am Anfang auf, dass er viel der amerikanischen Aussprache übernommen hat, das aber nicht durchzieht.

Agree. Processes stands out every time he says it: the first two vowels are good (for AE), but the last "eez" sounds as if said by someone who learned BE first and hasn't quite gotten away from it.

The Auslautverhärtung is pronounced ("ant" instead of and) and, while not distracting for someone with knowledge of German, would be very noticeable for your average AE speaker.

In my opinion the accent quite good: identifiably German, yet mostly easily understandable. I struggled a bit on some of the words, but the topic is not something I listen to every day. Presumably peers in the field would find the presentation easy to understand.

I only listened to part of the presentation, but would give the accent 8 out of 10.

Edit: for those who don't know me, I am a native AE speaker (Midwest).

Maybe 8? My 10 out of 10 is native-level.

#14: I just realized how strange the 'v' in reservoir is in my own accent. A combination of v and w. I guessed it was a French origin word, and I am right. Straight from the French word réservoir. Sounds similar to the ending of French "au revior".

Ja, das hat Amy-MiMi in #13 mit dem Fachwort Auslautverhärtung gemeint, glaube ich. Mir war das nicht (bewusst) aufgefallen.

Just wondering, why do you ask?

Nun, so wie Hunde, und sehen sie auch noch so unterschiedlich aus, einander am Geruch erkennen, so erkennen sich deutsche Muttersprachler, wenn sie Englisch sprechen, in aller Regel gegenseitig schnell an der so vertrauten Sprechweise. Als ich den hier verlinkten Sprecher kürzlich in einer Online-Konferenz erlebt habe, hatte ich angesichts seines deutsch klingenden Namens einen solchen Akzent erwartet und war dann überrascht, eine Aussprache zu hören, die ich spontan als "echt amerikanisch" eingestuft hätte. Ich wollte einfach mal erfahren, wie muttersprachliche Ohren das empfinden. Offenbar ist sein Akzent zwar nicht stark, aber doch noch deutlich wahrnehmbar. Allerdings mag es von Bedeutung sein, dass die verlinkte Aufnahme schon 6 Jahre alt ist. Mittlerweile ist seine Aussprache velleicht noch "echter" geworden.

OK! Thanks for answering that somewhat impertinent question.

Just for the record, I also quickly concluded that the speaker had a German accent, and that after just a few seconds. (I don't think I listened for more than 15 or 20 seconds when I first saw your question.) But on rehearing the segment just now, I tried to identify the reason. I think the "Auslautverhärtung" (the devoicing of final voiced stops) is the main clue; faintly detectable in the "D" of "Good afternoon" at the very start; more so in the "D" of "field experiments" (the "D" is practically dropped there), and clearly so in the final "D" of "conducted".

The "R" of "beer" is very American, but almost gives the impression of having too much weight put on it, almost as if to compensate for a native tendency to drop the final "R".

Anyway, that's my amateurish contribution to the analysis. (I think we can confidently rule out the speaker being French, or Japanese.)

#25: Er hat den Namen seines Kollegen mit dem italienischen Namen komplett falsch ausgesprochen (und noch nicht mal richtig gelesen). Schande über ihn!

Woher willst Du denn wissen, wie der in Frankreich geborene und in den USA forschende Herr seinen Namen im US-Kontext ausspricht? Einen Lesefehler angelsächsischer Intonation höre ich nicht.

Late to this thread, but an AE perspective on the first 20 or 30 seconds: the first few words are ambiguous, but as soon as he says "hard," it's clearly a non-native (and to my ear, a German, but others have said above that many Americans can't place the accent -- I am guessing that's a class thing.) Then:

1. the "beer" is wrong,
2. the "y" in "anyways" is shortened in a way a native would never do (en--uh-way),
3. he does have an amazingly American "sooo,"
4. but "I don't see my talk yet" is also clearly non-native,
5. as is "targeting." "
6. Field experiments" has no discernible accent [I disagree with the previous poster about this],
7. "conducted" clearly does.
8. "Induced seismicity" is unintelligible but not because of accent -- he just cuts short the word.
9. There's nothing unusual about his "processes" for an educated AE speaker; that's a common variant.
10. But generally his 'r's are weak and his vowels are consistently off, and there's also an exaggerated clipping off of sounds between words -- all the same reasons why it's hard for AE people to speak German like a native, but in reverse!

Generally I think the most remarkable thing about this person's speech is that he occasionally does speak entirely without a German accent; one could isolate clips of this that would sound like a native speaker. While no native speaker listening to this talk is going to believe he's an English native speaker, his accent is very good. I think the people saying that it's mostly easily understandable are understating things here -- I don't think his accent interferes with comprehension at all, except for his pronunciation of "fault," which is a key term of his but throws me every time (he says it like 'fought', when it really needs the most ugly American pronunciation -- fall-t). I would kill for an accent like this in German.