24 July, 2002

A rainy day on the Matanuska.........

Well, my forcast from last night was wrong..... I awoke this morning to the patter of rain on my tent. No geophysics today......... The equipment used for both seismic studies and GPR are sensitive to moisture, so they canıt be used when itıs raining.

Dr. Baker was able to analyze the GPR data collected yesterday, and I have attached an image of this with an explanation. Dr. Baker decided to proceed with the vertical velocity study as planned. So I lugged more weights up the glacier to the test site where they were lowered into the hole. A total of 5 weights were placed in the hole, one at the bottom (96m) and then at intervals of 20m (80m, 60m, 40m, and 20m). Once the weather improves, we will gather data at the site to determine if we can image the weights at the various depths.

While on the glacier, I also scouted around looking for possible site for another hole. We are trying to locate and area that will produce minimal backround interference when GPR is used. Such features as debris bands and ice fractures can cause ³noise² that complicates the data interpretation.

The remainder of the day was spent cleaning up the many digital photos that I have taken, and cleaning up my computer. I have also responded to numerous email questions. I love to get them, keep them coming!!!

Life Is Good,

DT

GPR data from lowering the weight into the hole. The lighter colored bands at the top of the image represent ground roll, which is caused by the signal bouncing off of material near the surface. The top of the lower, light colored region is the area of interest. This is signal bouncing off of the weight as it was lowered. Notice the depth scale on the right side. Arrow 1 shows a slow rate of lowering. The rate was increased as shown by arrow 2, and then slowed again (arrow 3).