Honshu, should they have seen it coming?

I’m from Southern California, and lived most of my life in the San Fernando Valley.
I’ve been through a few quakes.
Being an engineer, I have a passing interest in these seismic events. Today I went to the USGS site and extracted the earthquake event data from 3/6-3/13. Of course most of the data was dominated by Honshu after shocks. In all there were 561 events over this period, I greped the data for Honshu, resulting in 385 of the data points.
What was I looking for? Simple,  I was looking for pre-quake events.

What I found:
There were 36 seismic events > 4.6 that preceded the 3/11 5:46AM 8.9 mega-quake. This swarm started with a 7.2 event on 3/9 2:45AM.

Honshu201103

Honshu Seismic Events 3/9-3/13

Did they think that the 7.2 pre-quake was a rogue event? Followed by after shocks?
Or, was it a signal of more to come?
Sadly, I guess we know the answer now.

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