Historic activity of Tambora can be classified into 3 stages (Pannekoek van Rheden, 1918) as follow:
The first: activity which generated lava flow from the main crater, and built shield phase of the volcano with estimated height of 1800 m.

The second : the activity was more explosive, generated loose material and varied by lava flow which ran down southeastward, southward and southwestward. At this stage the height attained of about 4300 m.

The third : when the powerful eruption took place and followed by caldera formation. Its product were pyroclastic fall and pyroclastic flow which covered almost entire the edifice.
A dense cloud near the summit was observed (Zollinger,1855)
Initiated by the thicker and black plume which appeared several months and weeks before the powerful eruption took place.  

April 5, a rumbling could be heard in Jakarta and Ternate.  

April 10 -11, the paroxysmal eruption occurred, its rumbling echoed up to Bangka and Belitung Islands. Ground shaking which occurred at the same time was felt up to Surabaya. In Besuki ( East Java ), the sea level rose up to 6 feet. Madura Island has been dark for 3 days covered by ash.  

April 12, Paroxysmal eruption lasted.  

July 15, the activity decreased.  


August, a strong rumbling still on as well as ground shaking. 
1847 - 1913
Eruption took place inside the caldera generated lava flow and formed a crater named Doro Api Toi