Hi All,

We had a great first day at the AGU and began with everyone's favorite topic; earthquake prediction. The topic of the lecture series we sat in on this morning was,
Something In The Way She Moves. (I am so glad they are selecting interesting titles these days!) Anyway, the lecture series was chaired by Dr. Paul Silver of Carnegie.

The first speaker, E.S. Cochran did a presentation on spatial and temporal pattern of shear wave splitting along the Hector Mine rupture zone. In studying this 10/16/99 7.1 earthquake, they found 5 meters of ground movement to the north and 1 meter of movement in the south. Splitting occurred in area's on either side of the fault, producing earthquakes, however, along the fault itself the seismicity had dropped to near background levels. Therefore, they feel the regional area is not healing as fast as the fault itself. Everything around the fault is fractured and remains that way.

Presentation #2 was delivered by Dr. Zhuang on ELF signals. They explored daily signals taken since 1979 and looked for patterns for earthquakes of M>4.0 within a 300km radius. They marked these with indications of what signals should be precursors to earthquakes. Then they ran earthquake catalogs to compare them to the ELF predicted quakes and found to some degree the predicted quakes using ELF did work. However, the percentage of success was not noted, nor was the exact time frame for this study.

Speaker #3, Dr. Marzocchi discussed long term interaction between parallel earthquake faults. They used data from two locations, one in LA and the other in Italy. This study is much the same as we have seen in the San Francisco Bay Area with earthquakes on one fault, mirrored later by another quake on the parallel fault. From the information given, it does not appear there is anything new in this regard.

Dr. Piersanti then delivered his research he performed in looking at large earthquakes occurring along the Pacific Ring of Fire. From his research he concluded that 8.0 or larger magnitude earthquakes would trigger 8,000 other events.

At this point our lecture chair, Dr. Paul Silver delivered an interesting data review of seismic scatters which occurred in Parkfield in 1993. From borehole strainmeters, they noticed all of the meters showed an abrupt change along the San Andreas Fault showing accelerated slip. There was no indication of any of the data indicating any future outcomes, however, making note that the long term instruments installed in Parkfield did note this change, absent of earthquake activity.

Of course b-value had to be a topic discussed in this series of lectures and Dr. Schorlemmer who co-authored with D. Jackson, S. Weimer and M. Wyss did a study of the Parkfield area. While using b-value in M<4.0 earthquakes indicated that an earthquake should have occurred in Parkfield in 1993. They found they could not conclude the research as they had an absence of M>4.0 to use for their study.

Saving the best for last of this series, both Don and I were delighted to learn about a series of earthquake prediction projects underway in Iceland. The presenter of this lecture was Dr. R. Stefansson who said Iceland is a natural laboratory for short term earthquake prediction due to the ability to view the surface of the land, unlike most areas which are covered with foliage or buildings. In one particular instance a 6.1M earthquake occurred and from viewing the sequence of events following the quake, they felt another 6.0 or larger, earthquake would emerge. They placed emergency workers on notice of this event and 25 hours later a 6.6M event did arrive. These earthquakes were 4 days apart. There are four parts to this program and with each part the data collected is expanded and the long term projects look very impressive. Dr. Stefansson did express that this prediction was not delivered to the public, however, they are working toward the time when they will be able to do so.

In the midst of this lecture series we connected with Dr. Roger Musson, our old board poster, who this year is an invited speaker. We had a very nice chat and will meet again in the days ahead.

So we had a great first day at the AGU despite the weather. It was horrid. Cold, very damp and partly cloudy to cloudy and it even tried to rain on us. Having arisen at 4:30AM today to make sure we didn't miss any of this lecture series, both of us are more than pleased with the information we received.

This year, unlike past years, most of the graph data was presented via an expanded computer screen, though a few chose to use the overhead projector. On the humorous side one guest speaker from a foreign country had a little difficulty saying the word "earthquake." At each attempt it came out as "earthcake." At first I wasn't sure what I heard and then after ten or so uses of earthcake, it was apparent I did hear it correctly the first time. (Now trying saying that yourself. Earthcake.)

As I was taking a momentary break by myself, I found myself being tagged. Someone actually walked up to me and read my badge. So I thought to myself, yeah, you've been tagged.

We're off to a terrific start this year with lots more to come.

Petra & Don

• The Seismic Safety Zone