A vacancy shall be deemed to occur in the Council upon the presentation of a written resignation to the Mayor or the Vice Mayor, which resignation shall be effective immediately unless a later time is specified therein, upon the death of a Council member or the determination by the Council that a member of Council ceases to possess or has violated any of the qualifications of the office of Council member, and upon the removal of such Council member as provided in Section 12.04 of this Charter. Any vacancy in the Council shall be filled by a majority vote of the remaining members of the Council for the unexpired term. If the vacancy is not filled within thirty days after it shall have occurred, the power of Council to fill the vacancy shall lapse and the Mayor shall fill it by appointment immediately following the expiration of said thirty days. Any appointee under this section shall qualify under the provisions of this Charter and shall hold office and serve for the unexpired term and until his or her successor is elected and qualified.