I think when things like this happen, it usually falls under the category of "bad news is bad news" and people will want to reach out to friends/loved ones who may have been affected.
If my friend is going overseas for a month (and there aren't any terror attacks or plane crashes or whatever), I will probably assume they're doing just fine, haven't been mugged or gotten lost in the woods or anything unless I specifically hear otherwise.
Well put. "No news is good news" is predicated on no news. If nothing noteworthy happens then most people are fine with assuming you're doing fine until and unless they hear otherwise. But if some disaster (even a localized one) happens in the area where they know you are, that doesn't apply anymore.
That interpretation is actually at odds with my experience and how others have described it to me. I recall my mum describing the fear of receiving a telegram during the war. People would assure themselves nothing had happened to loved ones fighting because they had received no news. And when I myself was in London I think it was 7 7 bombings my family again assumed I wasn't caught up in it because they received no visit from the police. I didn't call until a long time after, despite evacuating the tube one stop from one of the bombs or something. Mind is fuzzy. Anyway, I think that is how the stiff upper lip stoic Brits are. Or were. Perhaps the modern generation are good for nothing self absorbed hugging kinds? Too much Anerican influence perhaps ;)