gstreamer1.0 can't load plugins; all gstreamer applications broken

Although all plugins (-base, -good, -bad, -ugly, and some others) are installed, gst-inspect-1.0 only shows:

:~$ gst-inspect-1.0
coreelements: valve: Valve element
coreelements: multiqueue: MultiQueue
coreelements: typefind: TypeFind
coreelements: tee: Tee pipe fitting
coreelements: filesink: File Sink
coreelements: queue2: Queue 2
coreelements: queue: Queue
coreelements: output-selector: Output selector
coreelements: input-selector: Input selector
coreelements: identity: Identity
coreelements: funnel: Funnel pipe fitting
coreelements: filesrc: File Source
coreelements: fdsink: Filedescriptor Sink
coreelements: fdsrc: Filedescriptor Source
coreelements: fakesink: Fake Sink
coreelements: fakesrc: Fake Source
coreelements: capsfilter: CapsFilter
staticelements: bin: Generic bin
staticelements: pipeline: Pipeline object

Total count: 2 plugins, 19 features
Segmentation fault (core dumped)

No combination of installed or uninstalled gstreamer packages will change the output or prevent the segfault; I tried everything that apt would allow except removing the -base plugins because that would uninstall nearly every software package on the computer. I did try reinstalling -base et al, to no avail.

Also tried rm -rf ~/.cache/gstreamer-1.0; no effect.

No gstreamer applications are working (totem, brasero, rhythmbox, etc).

gdb doesn't have much to say about the core dump:
:~$ gdb --exec=gst-inspect-1.0 --core=core
GNU gdb (GDB) 7.6.1-ubuntu
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
[New LWP 20049]

warning: Can't read pathname for load map: Input/output error.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `gst-inspect-1.0'.
Program terminated with signal 11, Segmentation fault.
#0 0x0000000000000001 in ?? ()