17 August 2008 A very successful trip to Rasshua

Ahhh. Another weather day. This time we're on our way to Chirpoi Island, where we are scheduled to spend one day, and then the north end of Urup Island, where we're hoping to spend two days working from the ship. But for now we'll sit behind the protection of Simushir Island, in Dushnaya Bay. Dushnaya Bay is one of the localities where Bre MacInnes has fantastic data from both before and after the 2006 tsunami. But, for better or for worse, we are not going to shore today because this latest low pressure system has given us some pretty snotty weather. Again.

It has been a pretty hectic past several days as we wrapped up a 9-day archaeology field camp on the south end of Rasshua Island. To add to the hectic-ness, we decided late on the 15th (after dinner, in fact) that the weather forecast was bad enough that we should hustle and break camp RIGHT NOW and come back ashore the following morning (the 16th) to finish up with the work on our two excavation units. It turned out to be a good decision - the low pressure system brought wind and rain, which made it difficult enough to finish our work on the 16th. If we had delayed breaking down camp, too, we would have had a pretty tough time of it.

We had made a list of three goals we hoped to accomplish while we were on Rasshua:

1) find and excavate a well-preserved midden;
2) find evidence of Ainu occupation (the group who lived in the Kuril ArchipelagoA chain of many islands. from the 14th or 15th Century, or maybe a bit earlier, into the 20th Century); and 3) help Bre collect the rest of the tsunami run-up data (from the 2006 tsunami) she needs for her PhD dissertation research.

We figured this was an ambitious, but mostly realistic list of goals. Ambitious because a) we have found relatively few preserved midden deposits over the past 2.5 field seasons, even with the nettles working on our side, b) we have found very little archaeological evidence of the Ainu, even though we know they had several large village sites in the Kurils during historic times, and c) the Pacific Ocean side of Rasshua, which is where the tsunami would have hit, has very few beaches suitable for landing safely, let alone for recording tsunami run-up data. But, by the end of our 9-day stay, we were so successful that we wondered if maybe we shouldn't have made our wish list a little longer!

If you read Laska Fitzhugh's "Guest Journal Entry" for Aug 8 (posted on Aug 11), then you know that we managed to find a very rich midden deposit. In Laska's words, it was a "bone jack-pot." We found the midden deposit using all the tricks from our archaeology survey team: characteristics of the surface vegetation (nettles), presence of artifacts and bones on an eroding exposure of sediment, and a "hit" (sea urchin and periwinkle shell) with our soil probe. Based on these pieces of information, we placed one of our excavation units (2 m X 4 m) right on top of the midden deposit. The bone preservation in this deposit is fantastic, and we were able to recover a large sample of bones and shell.

The midden deposit was so dense, in fact, that we decided to wash 100% of the sample through 1/8-inch (3.2 mm) screens (called "wet" screening). Typically we use 1/4-inch (6.4 mm) screens without water (called "dry" screening) for 25% of the sample and then bulk sample smaller portions of the deposit (i.e., take all of the sediment to the lab without screening any of it).

We know that 1/4-inch screening misses some items, but we often have to strike a balance between successful recovery of items and the time investment it takes to recover those items. In this case, we recognized right away that there was soooo much material, much of it very small fish bones and shell fragments, that there was no way we could realistically field sort the midden samples. So we bagged the midden deposits into sand bags 25 pounds at a time and carried them down the hill to camp for water screening (see photo).

As Laska indicated in her journal entry, a very conspicuous component of the midden is albatross bones. It isn't all that uncommon to find albatross bones in North Pacific assemblages. But this site is absolutely full of them - there are dozens of individuals represented in our sample, which is a lot for an excavation unit of this size. But interestingly, there is also a lot of very tiny bird bones and fish bones mixed in. This is part of why it is so important that we used the 1/8-inch screens to recover the bones. If we had only relied on 1/4-inch screens, we would have gotten a biased view of what size bones were in the deposit and, by extension, the relative importance of different species in the diet of the people who created the midden deposit.

One of the interesting things we learned from this excavation is that part of the midden deposit had been cut into by a subsequent excavation. This may, in fact, be the explanation for all the bones on the slope that Laska and I collected - they were dug up and tossed down the slope.

I've mentioned before the problems we have faced with the destruction of the prehistoric archaeological sites through all the historic military activities (excavation of defensive trenches and gun emplacements). The thing that is so interesting about this particular example, however, is that the cut into the midden deposit appears to have been the result of the construction of an Ainu house pit!

Although we make a big deal about the historic disturbances to archaeological sites, we have to remember that people have been modifying the landscape for as long as people have been people. In fact, the midden deposit, which we think dates to the Okhotsk Culture (roughly 1400-800 ybp, or years before present) may have cut into and mixed with a deposit dating to the Epi-Jomon Culture (~2300-1300 ybp).

And, finally, the house pit that we think is Ainu was, in turn, cut into by a military trench (the excavation of which may have also contributed to the accumulation bones on the surface of the slope).

With so many different "disturbance" events, you can see how important it is that we understand how the various layers of sediment were deposited. If it weren't for the detailed information we can get from "marker" tephras, interpreting the sedimentary strata would be much more difficult!

One of the most important "marker" tephras on Rasshua comes from the eruption of Ushishir Volcano, which is only about 25 km (about 15 miles) away. It erupted about 2000 years ago, and covered the south end of Rasshua with a thick layer of pumice and volcanic ash (only barely visible in Photo Two of Three). We will have to wait to see what the radiocarbon dates tell us about whether or not the eruption of Ushishir caused people to leave (or be forcibly removed from) south Rasshua. But for now we can say with certainty that people lived there when it happened, and that people lived there again afterwards. If south Rasshua were unoccupied for some time after the eruption of Ushishir, hopefully our samples will help us figure out how long that lasted!

I know I haven't talked at all about Bre's work to collect tsunami run-up data for Rasshua. But this entry is already pretty long, so I think I will just say that Bre was able to find two beaches on the Pacific Ocean side of the island where she was able to land safely and collect data on how large the tsunami was where it hit Rasshua (Matua still has the highest recorded run-up from the 2006 tsunami). Maybe I'll be able to get Bre to write a journal entry describing more of her results!

The rest of our "weather" day will be spent organizing all of our samples for shipment back to the United States. We have lots of different permit requirements we have to deal with - both for Russian and American government officials. So, while we always wish we could conduct more scientific research, this weather day will be put to good use.

Meanwhile, moving back to the ship after 9 days of camping means lots of things for our team. It means showers, running water, and dry clothes that don't smell like wood smoke. But it also means sharing the meal line with dozens of other people. And pitching seas. And Kaoru Tezuka-san and I cramming back into our tiny cabin space! The ship's crew still hasn't quite figured out why many of us are more comfortable camping - even when it's raining - than we are on the ship!

--Dr. E