Radar Correlation Big Island

RADAR IMAGES OF HAWAII

Radar Correlation, E. Big Island

We can also use radar interferometry to detect changes on the surface due to the formation of new lava flows. In this image, we compare JERS-1 radar data taken about three months apart. Where there are good fringes we can assume that there has been no change on the surface. But down-slope from the Pu'u O'o and Kupaianaha vents, we can see that there is an area where the map is black. This area has no correlation between the two images, and is due to the formation of a new set of lava flows.

We can compare this radar image with the map prepared by the U.S. Geological Survey at the bottom of this page. This map shows that the new flows were all part of Episode 55, which took place on February 20th, 1998. Had the Survey's map not been made, we would have been able to use the radar image to plot out the area of the new lava, but we would only have been able to say that the new flows formed sometime between the two image acquisition dates.