I've really delved into this, and I can say now with confidence that the immediate death toll from the blast shouldn't be in the thousands or anything, perhaps not even in the hundred.

Judging from videos and photos of damaged areas, I've concluded that the blast is most definitely 1 kiloton, but not more than 3.0 kilotons. The 2.9 kiloton blast Nova SCotia that happened a while back killed 2000 people. Know that this was a 2.9 kiloton blast in an area that has 44 people per square mile (granted, in a heavily populated area of personnel).

Some people have thrown the 7000 to 70000 death toll around based purely on the population density of Tianjin. This case, however, is much different, Tianjin may have a density of 3000 people per square mile, but this was a port we're talking about.

I even went to the famous Nuke Map to get some scale. I placed it right at the center of the blast site, and it seemed mostly correct, anyone within a mile of that blast would most likely have died, but it couldn't even be that many.

In fact, I even looked at the Nuke Map casualties list (by the way, the fireball was the same radius as the fallout meaning the fallout deaths were not considered). The death toll in the simulation changed based on area density, however, it never exceeded 100 people unless I was moving closer to the residential areas (which, surprisingly enough, was where all the surviving videos were taken from).

The blast should not have killed many people, in fact, the death toll may be inaccurate and subject to rise, but I doubt many people would have died from it. Even then, I was running the simulation at 3 kilotons, which is the highest that thing could go.

To further advanced my speculation, the earthquake detector 23km away from the explosion detected a 2.9 magnitude created from the blast. Mind you that a 5 kiloton nuclear weapon can create a 4.0 magnitude. So this explosion being only 2 kilotons isn't soo far off. In fact, I'm willing to bet that it was around their.