A total of 23 maar structures have been drilled by the ELSA Project using 61 sediment cores with a total length of 2171 m length. The drilling locations usually have been placed in the middle of a maar structure, but a good accessibility for the large drilling rig made it sometimes necessary to shift the drilling site, preferentially to the outflow side, if the maar is fed by a creek. Environmental protection areas limit the access to many maar lakes and infilled structures, in particular if swamps fill the center part of the dried-out lake. 

It was the intention of ELSA to drill indeed all maar structures and decide on those, which are the most suited to arrive at annual resolution records. The cores used for the last 60,000 years are those of the ELSA-20 record; the extension of the annual resolution time series back to 130,000 years and finally back to 470,000 yr b2k is in progress and will be presented with the upcoming ELSA-23 record.

ELSA has drilled also outside the West Eifel Volcanic Field. We studied the volcanic crater lake of the Laacher See (Sirocko & Diensberg, in prep.), but also classical sites from past interglacials in northern Germany; in particular sediment cores from Munster, Bonstorf, Essemühle and Redderstall. The respective cores are also in the ELSA core repository and have been partly already analyzed, however, not published yet.

Table 1 presents the list of all ELSA cores with geographical coordinates.