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Why Some Volcanic Islands Grow Larger After Eruptions — Instead of Shrinking

Why Some Volcanic Islands Grow Larger After Eruptions — Instead of Shrinking

为何某些火山岛在喷发后反而变大而非缩小

  1. Most people think eruptions destroy land — but underwater lava flows can add new coastline rapidly.
  2. When hot basalt erupts into cold seawater, it cools fast and builds steep, glassy cliffs called pillow lava.
  3. Repeated underwater eruptions pile up layers that eventually break the sea surface as new land.
  4. Hawaii’s Big Island grew over 500 acres during the 2018 Kīlauea eruption thanks to such flows.
  5. Unlike explosive ash clouds, quiet effusive eruptions push out dense rock that doesn’t blow away.
  6. Scientists measure island size changes using satellite radar and drone photogrammetry.
  7. Some islands shrink later due to wave erosion — but initial growth is real and measurable.
  8. Lava deltas form where rivers of molten rock enter the sea and steam violently on contact.
  9. These deltas are unstable at first but harden quickly into solid basalt platforms.
  10. Geologists monitor new lava entries closely because sudden collapses can trigger deadly steam explosions.
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