Narrative:

Leveling FL360 while accelerating to cruise through 240 KIAS; a high-frequency vibration was felt through the elevator controls. We slowed to 200 KIAS and the vibration remained. The vibration was pronounced enough that we decided to [advise ATC] and divert to [a nearby airport]. We were given a lower altitude and a heading for the descent. We kept the airplane at 200 KIAS for the entire descent. Dispatch noticed we were descending and sent an ACARS inquiry. We explained the situation and they sent us info on [the airport]. I was concerned about the effect changing airplane configuration would have; so I elected not to use speed brakes for the descent and to do a no-flap landing. We briefed the flight attendants about the situation/divert and told him we didn't feel it would be necessary to issue brace commands. The landing occurred normally on 18L at 45;100 pounds. The rescue trucks were called off and we taxied normally to the gate. Post flight inspection revealed nothing unusual.conditions were ideal for this occurrence. The weather was cloudless and smooth all of the way to the ground. The vibration occurred during a low workload phase of flight and traffic at the diversion airport was light. The duration of the descent allowed sufficient time to complete the necessary diagnoses and run all pertinent checklists. The undesired state was; of course; an elevator that didn't feel right.I'm not sure what the cause of the vibration was; but I felt the crew; dispatch; and ATC communicated well.

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Original NASA ASRS Text

Title: EMB-145XR Captain reported diverting to an alternate airport after noting a high-frequency vibration in the elevator.

Narrative: Leveling FL360 while accelerating to cruise through 240 KIAS; a high-frequency vibration was felt through the elevator controls. We slowed to 200 KIAS and the vibration remained. The vibration was pronounced enough that we decided to [advise ATC] and divert to [a nearby airport]. We were given a lower altitude and a heading for the descent. We kept the airplane at 200 KIAS for the entire descent. Dispatch noticed we were descending and sent an ACARS inquiry. We explained the situation and they sent us info on [the airport]. I was concerned about the effect changing airplane configuration would have; so I elected not to use speed brakes for the descent and to do a no-flap landing. We briefed the Flight Attendants about the situation/divert and told him we didn't feel it would be necessary to issue brace commands. The landing occurred normally on 18L at 45;100 LBS. The rescue trucks were called off and we taxied normally to the gate. Post flight inspection revealed nothing unusual.Conditions were ideal for this occurrence. The weather was cloudless and smooth all of the way to the ground. The vibration occurred during a low workload phase of flight and traffic at the diversion airport was light. The duration of the descent allowed sufficient time to complete the necessary diagnoses and run all pertinent checklists. The undesired state was; of course; an elevator that didn't feel right.I'm not sure what the cause of the vibration was; but I felt the crew; dispatch; and ATC communicated well.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.