IDENTIFYING FORMER CENTERS OF VOLCANIC ACTIVITY ON LESVOS ISLAND, GREECE

Identifying the major source areas of volcanic materials on Lesvos Island, Greece, has been achieved by using remote sensing, a DEM, drainage network evaluation, and field examination.

A newly enhanced LANDSAT 5/TM image clearly delineates centers of extrusive volcanic activity. The island's drainage network shows radial drainage patterns in five areas and possibly a sixth. Point sources of volcanic materials were confirmed by ground observation of craters, some with central cones. Numerous, isolated volcanic plugs with extensive columnar jointing suggest additional point source activity. Specific centers of volcanic activity in the form of craters and domes are located near several villages: northwest of Vatousa, southwest of Thermi, near Agra, and at Mt. Lempetimnos. The volcanic activity in these locations was responsible for the extensive deposits of lavas, ash, ignimbrites, and tuffs in the central and western part of the island. These deposits, in turn, are related to the presence of the extensive petrified forest mainly located there.

The Miocene age volcanic activity appears in some cases to be fault aligned and is associated with regional crustal stretching and the resultant system of horsts and grabens. Similar patterns of volcanism and faulting have been identified in the Neogene-Quaternary Edremit graben in Asia Minor to the east of Lesvos.