Question

ice land why do most earthquake's occur near plate boundaries, if two continents keep colliding or millions o ears, what might happen tot eh land, predict what earth might look like 100 million years in the future if plates keep moving

Answer 1

Short answer first:
- Most earthquakes happen near plate boundaries because plates grind past, pull apart, or collide there — and those motions build up stress that’s released suddenly along faults.
- If two continents keep colliding for millions of years they will weld together and build very large mountain ranges (thickened crust, lots of earthquakes while they’re active), then those mountains slowly erode over tens of millions of years.
- Predicting Earth 100 million years from now is possible in broad strokes but is uncertain. Plausible outcomes include new mountain belts, continents sutured together into a larger landmass (a future supercontinent), a changed distribution of oceans, and continued earthquakes concentrated at the active plate boundaries that remain.

Explanation and details

Why most earthquakes occur near plate boundaries
- Plate motions create stress. The Earth’s outer shell (the lithosphere) is broken into plates that move relative to one another. Where they meet the rock is deformed and stress accumulates. When the stress exceeds the strength of rock the rock breaks or slips and that produces an earthquake (the elastic rebound idea).
- Types of plate boundaries and related quakes:
- Convergent (collision/subduction): plates push together. Subduction zones produce the largest quakes (megathrusts). continental collisions create shallow crustal quakes (e.g., Himalaya).
- Divergent (spreading ridges): plates pull apart; earthquakes are generally smaller and shallower (Iceland sits on the Mid‑Atlantic Ridge).
- Transform (sliding past): lateral slip on faults produces strike‑slip earthquakes (e.g., San Andreas).
- Local examples: Iceland is especially seismically and volcanically active because it sits on a spreading ridge (Mid‑Atlantic Ridge) and above a mantle hotspot; that combination produces frequent earthquakes and eruptions.

What happens if two continents keep colliding for millions of years
- Continual collision causes crustal shortening and thickening: rocks are folded, thrust over each other, and the crust grows thicker.
- Mountain building (orogeny): uplift forms high mountain ranges (the Himalayas are the classic present example from India‑Asia collision).
- Intense seismicity during active collision as faults accommodate motion; large earthquakes are common.
- Metamorphism and crustal melting at depth can generate magmatism. Over tens to hundreds of millions of years erosion reduces peak heights and deposits sediments in surrounding basins.
- Ultimately the collision may permanently weld the continents into a single larger landmass (a suture zone marks where they joined).

What Earth might look like in 100 million years (plausible scenarios)
- Predictions are inherently speculative because mantle convection and plate boundary initiation can change directions unpredictably. Still, paleogeographers use current plate motions to extrapolate a few plausible outcomes. Commonly discussed scenarios include:
- Amasia: North America and Asia drift together across the Arctic and collide, forming a large northern landmass.
- Pangaea Proxima / Novopangaea: continued convergences produce a new supercontinent somewhere (different reconstructions put it in different places).
- Likely broad features in ~100 Myr:
- Some oceans will change shape: parts of the Pacific may shrink as subduction eats its margins; the Atlantic may widen or eventually develop subduction margins and begin to close (timing uncertain).
- New mountain belts where continents converge (continued Himalayan uplift while India continues to press into Asia; possible new ranges where other collisions occur).
- Continents shifted hundreds to a few thousand kilometers from their present positions — coastlines, sea passages, and climate zones will change.
- Earthquakes will still concentrate along the newly active plate boundaries and sutures; interiors of large continents will remain relatively quiescent.
- Climate and biodiversity will change as continents move (continental configuration affects ocean currents and climate).

Bottom line
- Plate boundaries are where most earthquakes happen because that’s where stress from plate motion is concentrated.
- Long, sustained continental collision builds mountains, thickens crust, causes lots of earthquakes while active, and eventually joins the continents into a new landmass that later erodes.
- In 100 million years the continents will likely be in very different positions, with new mountain ranges and perhaps the early stages of a new supercontinent — but exact details are uncertain and depend on how plate motions evolve.

If you want, I can:
- Show one or two example maps of proposed 100 Myr futures (Amasia, Pangaea Proxima).
- Explain Iceland’s earthquakes and eruptions in more detail.