Question

who and when tectonic theory was propounded ?

Answer 1

 Alfred Wegener in 1912

Answer 2

Alfred Wagner in 1920.According to the generally accepted plate tectonic theory, Earth's surface is broken into a number of shifting slabs .These slabs move relatively above a more mobile zone at rates as great as a few inches every year.Most of the world's active volcanoes are located near the boundaries of  shifting plates , called plate-boundary volcanoes.