The diagram illustrates how the Hawaiian Islands chain made off at (were made in) the Pacific Ocean by volcanic activity.
Overall, it can be seen that the Hawaiian islands were developed by volcanic activity from under the Earth.
The island chain formed as an effect (a result) of volcanic activity dating back to 80 million years ago. Firstly, the eruption process started from under the Earth approximately 2883 km down below. The movement of Pacific plate, causing a shift of the Pacific tectonic plate (7-9 cm per year) into the north-west direction. Thus, it affected the "hot spot" and created a new path of magma material exited (to exit) out and magma spume came into (onto) the surface of the Earth. The cycle repeated and then the newest, youngest volcano was created, which were (was) built up by numerous eruptions.
Finally, a continuous activity by Pacific ocean's plate creates several new islands next to newest volcanoes caused by the Earth plate shifting every year and formed (, forming) an archipelago of Hawaiian islands. 
The diagram illustrates how the Hawaiian  
Islands
 chain made off at ( 
were made
 in) the Pacific Ocean by volcanic activity. 
Overall
, it can be  
seen
 that the Hawaiian  
islands
  were developed
 by volcanic activity from under the Earth.
The  
island
 chain formed as an effect (a result) of volcanic activity dating back to 80 million years ago.  
Firstly
, the eruption process  
started
 from under the Earth approximately 2883 km down below. The movement of Pacific  
plate
, causing a shift of the Pacific tectonic  
plate
 (7-9 cm per year) into the north-west direction.  
Thus
, it  
affected
 the  
"
hot spot 
"
 and created a new path of magma material exited (to exit) out and magma spume came into (onto) the surface of the Earth. The cycle repeated and then the newest, youngest volcano  
was created
, which were (was) built up by numerous eruptions. 
Finally
, a continuous activity by  
Pacific ocean
's  
plate
 creates several new  
islands
  next
 to  
newest
 volcanoes caused by the Earth  
plate
 shifting every year and formed (, forming) an archipelago of Hawaiian  
islands
.