Overall:
After reading over the draft it's pretty clear that it's pretty unfinished. A lot of the ideas you outlined in your post, such as the race of Lovecraftian underwater creatures weren't featured, at least as far as I could tell. Still, I like the ideas you're going for here. Exploring the themes of isolation while incorporating Lovecraftian horror sounds like an excellent mix to me.
The log featuring Blackburn is written fine, but as it is right now though, I can't really get invested in what's going on. One problem is that we only see Dr. Blackburn after their already insane or at least starting to turn. In order for us to feel the existential terror that you're going for, we need to have some logs that were recorded before or immediately after the incident. They don't have to be too long, but a log showing us the completely sane Blackburn, a log showing a slightly paranoid and trying to keep it together Blackburn, and finally a full on crazy log is the type of arc I'd like to see. Another article that deals with isolation (and is my personal favorite in fact) is SCP-3001. Something to take away here is that we can occasionally see a man who is terrified and sad in between the crazy and incomprehensible.
For your Conprocs and Description, a lot of it is overexplained and breaks with clinical tone. I'll try to point these places out and suggest how to fix them later on, although I'm by no means an expert.
Specific:
I'll be using strikethrough for what to take away and green for what to add.
Scranton reality anchors installed 1498.5m below sea level at 37.7333° N, 121.8317° E; 36.7333° N, 122.8317° E; 35.7333° N, 121.8317° EE and 36.7333° N, 120.8317° EE and focused on their central point: 11.3733° N, 142.5917° E 36.7333° N, 121.8317° E
Scranton reality anchors installed 1498.5m below sea level at 37.7333° N, 121.8317° E; 36.7333° N, 122.8317° E; 35.7333° N, 121.8317° EE and 36.7333° N, 120.8317° EE and are to be focused on their central point: 11.3733° N, 142.5917° E 36.7333° N, 121.8317° E
as well as constant active sonar and passive sonic scanning of the ocean to ensure nobody enters submerged
as well as constant active sonar and passive sonic scanning of the ocean to ensure nobody enters submerged no submersible vehicles enter.
The anchors are to be monitored for damage every 72 hours and if damage has occurred they are to be repaired or replaced immediately.
The anchors are to be routinely examined monitored for damage every 72 hours. and if If damage has occurred is detected they are to be repaired or replaced immediately.
Submarine patrol drones equipped with radar capabilities and Spearfish class heavyweight torpedoes are permitted to use lethal force to ensure no unauthorised access.
This seems a bit much. The misinformation is usually enough to keep people back. (If it's not then it needs to be) The use of deadly force is usually not authorized as people can just be amnestisized, and disappearances would only draw more attention.
As per UAO-ΥΦ-19's procedures, any further non-foundation exploration of the Mariana Trench has been dissuaded thanks to Director Barnes' connections in the National Oceanic and Atmospheric Administration (NOAA) and the European Marine Biological Resource Centre (EMBRC).
Not sure about attributing the Foundation's connections to these organizations to just one man. The common understanding is that the organizations help the Foundation because it's in all their best interests what with the rampant anomalies and all, not because of personal ties.
As per UAO-ΥΦ-19's procedures, any further non-foundation exploration of the Mariana Trench
Pretty sure this is just a typo, but in the rest of the article it's the Monterrey Canyon, not the Mariana Trench.
Previous foundation records
In my experience "foundation" should be capitalized.
Description: SCP-???? is an experimental deep-sea living environment and research station located in the Monterey Canyon; 1498.5km below sea level, at 11.3733° N, 142.5917° E.
Considering many people read the description first to see if the article is interesting, the first line of the Description has to be eye catching. My main concern is that the anomalous nature of the station isn't even described until the Recovery section.
Initially, the submerged station was able to communicate via 21mm fiber optic cable
The use of '21 mm' is a bit extraneous and will confuse someone just skimming as to the length of the cable.
Dr. Blackwell (the only resident prior to the loss of Valkyria-1)
You've detailed a pretty large underwater station, so only having a single researcher there immediately breaks immersion and ends up feeling like an excuse to explore themes of isolation. An easy write around is to simply have the rest of the crew die in the first incident, or perhaps they're all transported somewhere else. Alternatively, you could have the crew all be in the station at first, but over time the succumb to either the creatures you mentioned or just the isolation. Eventually, only Blackburn is left clinging to their sanity, but even they will be gone soon too.
The world was told that due to underwater currents caused by the hurricane, the submerged environment was destroyed by falling rocks. In reality, it seemed to have completely disappeared. The area was scanned with multibeam echo-sounders, but no trace of the Valkyria-1 was found. Instead, a minor disturbance in spacetime centered around the location the Valkyria-1 should have been was discovered. Seemingly inert, the location was named UAO-ΥΦ-19 and never deemed necessary of official SCP designation, and minor discouragement of further exploration by Director Barnes was deemed suitable containment measures.
The world was told Misinformation was distributed that due to underwater currents caused by the hurricane, the submerged environment was destroyed by falling rocks geologic activity. In reality, it seemed to have completely disappeared. The area where Valkyria-1 was last located was scanned with multibeam echo-sounders, but no trace of the Valkyria-1 was found remnants were recovered. Instead, a A minor disturbance in spacetime centered around the location the Valkyria-1 should have been was previously located was discovered at this time. Seemingly inert, the location was named designated UAO-ΥΦ-19 and never deemed necessary of official SCP designation, and minor discouragement of further exploration by Director Barnes was deemed suitable containment measures.
Not sure about the last part, as a distortion in spacetime would probably be considered an SCP, and simply discouraging people from interacting with it would never be considered proper containment measures.
a foundation-led expedition to research the anomaly was finally deemed viable and necessary.
a foundation-led expedition to research the anomaly was finally deemed viable and necessary.
