You can search for Tephra at Wikipedia or Wikiversity, learn how to search, or browse all books.
volcano is a tall, conical volcano composed of many layers of hardened lava, tephra, and volcanic ash. These volcanoes are characterized by a steep profile
15 KB (1,875 words) - 03:43, 6 November 2015
ones, to observe volcanic eruptions, collect eruptive products including tephra (such as ash or pumice), rock and lava samples. One major focus of enquiry
17 KB (2,921 words) - 20:57, 23 October 2013
The lower 250-350m are characterized by common fine-grained, rhyolitic tephra (acid air-transported volcanics), i.e. yellow-white pumice tuffs (often
69 KB (11,070 words) - 08:58, 18 October 2015