Submarine Volcanoes Polygons (100k)

Submarine volcanic structures and eruption centers including hydrothermal activity, mapped by various national and regional mapping projects and recovered in the literature. Locally polygons are extended on land to include the emerged portions of the volcanoes. Polygons represent areas larger than 4 hectares. (for smaller areas, see volcanoes points layer) Note: blank areas do not necessarily correspond to no occurrence.本数据集包含经多国及区域测绘项目填绘、且已见于公开文献记载的海底火山构造与喷发中心，涵盖热液活动相关内容。局部多边形向陆地区域延伸，以覆盖火山出露地表的部分。所有多边形表征的区域面积均大于4公顷；若需查询面积更小的相关区域，请参考火山点图层。注：空白区域并不必然代表无相关目标分布。