Date: 201412
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Rain
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Turbine Engine
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; General Declared Emergency
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: We were level at 6;000 feet; in IMC; and being vectored northwest of airport; eventually planning to land south. Approximately 10-12 minutes before landing; fluctuations were observed on the #1 engine vibration indicator and vibrations were felt from the flight deck.With the situation persisting; the First Officer (FO) Pilot Monitoring (PM) looked up the Engine Vibration checklist in the QRH; but quickly accessing the page was problematic as he noticed the Engine/APU table of contents referenced the incorrect page for the Vibration checklist (after the flight it was discovered that the Engines/APU table of contents page was incorrectly dated.) In very short time; the engine vibration/noise became much worse. With FO concurrence; the #1 engine throttle was brought to idle then; after a short period of time; power was slowly brought up; but the vibration indications increased and the engine did not sound normal. I called for the Engine Shutdown checklist and an emergency was declared with approach as we started on downwind. Just prior to the fuel lever being placed to cutoff; I noticed the ENG 1 Oil Filter Bypass light on the upper DU blink momentarily. The Engine Shutdown checklist was completed. We were turned onto a 14 mile final; were quickly established on the glideslope; and broke out of the clouds. The winds were out of the south; no more than 5 knots with light rain. Landing was uneventful with a weight of about 135;000 pounds and MAX brakes selected. We turned off with no further assistance needed. As we taxied to gate under our own power; I asked the FO to call operations and inform them that we would be arriving at the gate with #2 engine running until parked. I was concerned about ramp personnel approaching the right side of the aircraft when they are accustomed to the #2 engine normally being shut down. After the flight; we had time to talk to the flight attendants and explain what happened. Because of the high workload in the approach environment prior to landing; we did not have time to brief the flight attendants regarding the engine being shut down. They had felt the vibration and mentioned that passengers had observed sparks and/or a flame coming from the back of the left engine. Our lead FA had also noticed the same.


Second narrative: [Report narrative contained no additional information].


Synopsis: B737 flight crew reported they shut #1 engine down in descent for landing because of excessive vibration.