Eug TRACON controller reported an aircraft descending below the minimum vectoring altitude.

Attributes
ACN	1559285
Time
Date	201807
Local Time Of Day	1201-1800
Place
Locale Reference	EUG.TRACON
State Reference	OR
Aircraft 1
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 7
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

Narrative:

I descended aircraft X to 6;000; they read back 6;000. I gave another aircraft instructions and noticed aircraft X was at 4;000 in a 4;500 MVA.

Original NASA ASRS Text

Title: EUG TRACON Controller reported an aircraft descending below the Minimum Vectoring Altitude.

Narrative: I descended Aircraft X to 6;000; they read back 6;000. I gave another aircraft instructions and noticed Aircraft X was at 4;000 in a 4;500 MVA.

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.