I doubt they have radios. they probably use cell phones in my honest opinion
The USGS has lots of frequency allocations and they are busy in the areas where the USGS is active, for sure.
From the March 2005 Fed Files column:
Searching my information about possible USGS radio frequencies turned up hundreds of them, so I don’t have room to list them all, but here is what I have heard in use at Mt. St. Helens, Washington:
167.0750 MHz – Input to 168.4250 repeater
168.4250 MHz – Repeaters on both the north and south sides of Mt. St. Helens
168.4500 MHz – Possible simplex use
169.8250 MHz – USGS Nationwide
The USGS uses many different devices for monitoring the volcano and it’s activities, including GPS, laser-height sensing equipment as well as seismic sensors. Here are some sensor frequencies that have been heard in southern Washington:
162.1250
162.1750
162.2000
163.3970
163.6050
163.6600
163.9000
164.0060
164.6600
164.8450
165.8100
166.4180
167.8150
406.1500
409.6000
412.1250
416.5500
416.79375
417.7250
- Chris