Something seismic going on, maybe?
Yeah, that pic didn't look like it could have been a seismic thing. Could they have put something in the gas? Let's see if they published the time span of the 50 blasts…. Or maybe this wasn't really gas.
https://www.cbsnews.com/news/lawrence-ma-fire-gas-explosion-suspected-2018-09-13-live-updates/
This gives the scope of the problem. It's a wide area, it seems. I don't see anything about the span of time they occurred.
As for tremors, USGS should show those, but they've been known to delete stuff. They're not showing anything right now.
https://earthquake.usgs.gov/earthquakes/map/#%7B%22feed%22%3A%221536888083859%22%2C%22sort%22%3A%22newest%22%2C%22basemap%22%3A%22grayscale%22%2C%22restrictListToMap%22%3A%5B%22restrictListToMap%22%5D%2C%22timezone%22%3A%22utc%22%2C%22mapposition%22%3A%5B%5B35.174%2C-81.738%5D%2C%5B47.872%2C-65%5D%5D%2C%22overlays%22%3A%5B%22plates%22%5D%2C%22viewModes%22%3A%5B%22list%22%2C%22map%22%5D%2C%22listFormat%22%3A%22default%22%2C%22autoUpdate%22%3Afalse%2C%22search%22%3A%7B%22id%22%3A%221536888083859%22%2C%22name%22%3A%22Search%20Results%22%2C%22isSearch%22%3Atrue%2C%22params%22%3A%7B%22starttime%22%3A%222018-09-13%2000%3A00%3A00%22%2C%22endtime%22%3A%222018-09-14%2023%3A59%3A59%22%2C%22maxlatitude%22%3A47.872%2C%22minlatitude%22%3A35.174%2C%22maxlongitude%22%3A-65%2C%22minlongitude%22%3A-81.738%2C%22minmagnitude%22%3A0%2C%22maxmagnitude%22%3A2%2C%22orderby%22%3A%22time%22%7D%7D%7D
It might be within that site somewhere. This isn't the only view it provides. If you want details like that, maybe watch a Dutchsinse video and see what he's looking at?
Would be interesting to know if the sites hit were their employees.