Sec. 9. (a) The office of executive becomes vacant whenever the executive:
(1) dies, resigns, or is removed from office;
(2) ceases to be a resident of the city;
(3) is convicted of a felony, as provided in IC 5-8-1-38; or
(4) is unable to discharge the powers and duties of the executive's office for more than six (6) months.
(b) The vacancy shall be filled under IC 3-13-8.