Other than tectonic activity, what can reshape a world's surface? Take our world and look at its surface geography: we have continents and oceans, mountains ridges and canyons, and so on. To my knowledge, most of it has been shaped by tectonic activity (feel free to correct me).
I'm looking into other things that would reshape a world on a large scale. It can be natural phenomena or artificial activities, it can occur over millions of years or in a matter of hours or days, and so on. Anything you can think of, which realistically would be able to change a worlds geography.
To be clear, I'm not looking for &quot;small&quot; regional changes (Mount St. Helen comes to mind), I'm looking for something that would at least reshape a big chunk of a continent, if not more.
At the same time, I don't want it to be so extreme to completely destroy the world (eg. Earth's early days meteor shower, which pretty much melted its entire surface, or worse).
Hope it makes sense...
EDIT: I've read some interesting replies so far. I'd like to point out that the changes I'm referring to would be noticeable on a world map.
For example, the creation of new landmasses (eg. volcanic islands), their disappearance, or their movement. Seas and oceans, mountain ridges, stuff like that.
Is there something that could explain the sea level lowering permanently, leading to new lands emerging? Other than volcanoes (and tectonic activity), are there other ways for mountains to form? Is there something that would explain a huge (as in the sized of a large nation like the US or China) depression to appear? Stuff like that...
Erosion is a powerful but slow and time consuming process that can make dramatic changes. The best example of this is the Grand Canyon. Carved by a river over at least 17 million years, 5000 to 10,000 feet deep, 277 miles long and 18 miles wide.
Erosion, whether it be due to wind, rain, water flow in rivers, glaciers is a major cause of geology, in the form of mineral grains, boulders and rocks to be mobilized and dispersed over a wide region.
Weathering is another force that reshapes the surface of the Earth. Australia is a perfect example of this. Weathering results in the physical breakdown of the of the surface geology due to weather, thermal stresses, frost, crystal formations and decomposition, oxidation, biological activity, alternating patterns of hydration and dehydration over a very prolonged period of time. The difference between erosion and weathering is erosion causes movement of material, weathering happens  in situ.
Fire tolerant plants such as eucalyptus and fire as a result of natural forms of ignition, such as  lightening  can change the botany of a large region, again see Australia. Eucalyptus has been described as a weedy tree that came to dominate a landscape when less fire tolerant plants became extinct.
Persistent fire or drought over a prolonged period can lead to permanent loss of flora resulting in desertification. Similarly, excessive rain due to climate change can lead to landslides and excessive erosion.