What type of plate boundaries are near hawaii, nepal and tokyo?

Question

What are the implications of this plate boundary type (what is happens at this plate boundary, what might happen at it in the future, how might this affect the city?

Answer 1

Hawaii is not on a plate boundary. Mona Loa is a shield volcano.

Tokyo is on the Eurasian/Pacific plate boundary

Nepal  is on the Eurasian/Indio-Austrailian plate

These areas are extremely tectonically active and prone to earthquakes and volcanic activity. Very likely to be hit by earthquakes and associated problems like tsunamis.

Answer 2

Hawaii is a hot-spot volcano, in the middle of an oceanic plate.  The plate is moving across the hot spot, creting a linear chain of volcanoes that gets progressively older away from the hot spot.

Nepal is in the Himalaya, a mountain chain which grew out of the collison of the Eurasian plate with the Indian sub-continent.  The great mountain chain is a result of the thickening of the crust where one continent is trying to override the other.  The Himalaya are still rising as a result of this collison and the continued northward drift of the Indian sub-continent.

Tokyo lies in a volcanic island arc, above a subducting plate.  The Pacific Plate is being subducted and the volcanoes form ing the island arc are above the down going plate.

You ask how it might affect the city - but you mention only one - Tokyo.  Because of its location above a subduction zone it is very prone to earthquakes.