Hi Todd:

All below is just IMO:

Somebody posted an article about how water pumping practices in the wider LA basin have contributed to strain measure variations (and some might say microearthquakes). This "contamination" of the data with regards to sleuthing fault movements has seriously happered efforts to decipher the "fault movement puzzle" going on in the area.

One recent revelation, it appears, is that microearthquakes below about M2.5 were not (until recently {see post below somewhere}?) entered into any catalogs for record keeping (and later retrieval and study) purposes. So for the geo-physical "fault movement" aspects this is a large detriment since the ability to identify the contribution from water pumping effects is diminished (in some eyes) without this data.

This is also, IMO, a deteriment to making more accurate short-term earthquake predictions (for the LA region) {which can't be done according to Lucy Jone's current understanding...but maybe she'll come around...see link posted in a message below}

This is also true to a degree in answering your question. Without records which reflect microeqs down to M0.8 or so...some key data was being lost...and the ability to declare what is "normal" for the area is hampered.

To continue my ramblings...patterning the microearthquakes appears to have some merit. There is prior evidence that clustering of micro-eqs in a small region is suggestive of larger magnitude quakes happening in these regions.

For example, some might say that the tight clustering of micro-eqs in LA might be an ominous sign of a larger quake on the horizon....others may say maybe not.

My thoughts are rather involved in this matter so I won't write a novel here.... I will just say that multiple conditions must come together for an larger earthquake event to happen (which I assume is a main interest).

Let's just say that on a scale of 1 to 10 (which is the liklihood of a large event (say > M5.5)) the clustering of micros around LA brings LA up to a 1 or 2 on the 10 scale. Depending on the other conditions, the probability for LA could increase or also decrease backdown to close to zero. These other conditions which escalate the probality have,IMO, not happend as yet.

So the short answer is: the LA deal is that water pumping may be confusing the picture And regardless the probability of a larger event is enhanced when clustering of micro-eqs happen. Therefore LA is slightly closer to a larger event...however the other conditions for moving up the scale to high liklihood have not happend as yet and may not for a while (wherein the micro-eq pattern cluster may change). So right now, don't expect anything greater than an M4-4.2 worst case...with magnitudes <= M3 more likely.

I hope that provided some useful thoughts to you. I think there will be a whole lot more useful information for you out there at some future date.