因為活火山離海非常近，火山噴發後熔岩遇到海水冷卻成了砂礫，形成了神秘的

因為活火山離海非常近，火山噴發後熔岩遇到海水冷卻成了砂礫，形成了神秘的黑沙灘。

結果 (英文) 1:

Because the active volcano from the sea, very close to the volcanic eruption of lava encountered seawater cooling became gravel, forming a mysterious black sand beach.

結果 (英文) 2:

Because the active volcano is very close to the sea, the lava after the eruption is cooled into gravel, forming a mysterious black sand beach.

結果 (英文) 3:

Because the active volcano is very close to the sea, after the eruption, the lava meets the sea water and cools into gravel, forming a mysterious black beach.