Map of Long Valley caldera showing locations of selected USGS hydrologic monitoring sites, the geothermal well field at Casa Diablo, and various geologic features referred to in the text. Numbered sites are described in the table below, which lists the maximum temperature in wells or the vent temperature in springs. The geologic features include Mammoth Mountain (the site of anomalous gas discharge that is killing trees), the Resurgent Dome (a highland region formed by repeated volcanic eruptions and magmatic uplift following the initial formation of the caldera 760,000 years ago), and the Inyo Craters Volcanic Chain consisting of numerous volcanic domes and phreatic craters that have erupted repeatedly over the past 10,000 years or so.

Number on map	Site Name	Site Description	Temperature (Celsius)
1	Big Alkali Spring	Hot Spring near Big Alkali Lake	57
2	Big Springs	Cold springs along Owens River	11
3	Colton Spring	Hot spring activated by earthquakes in the 1980's, but ceasing to flow in 1991 as a result of pressure declines from geothermal development	93
4	Fish Hatchery Springs	Four groups of spring vents; water used for fish rearing operations	11-18
5	Hot Bubbling Pool	Hot pool with no surface discharge; fed by hot springs at temperatures of 93 °C	~70
6	Hot Creek gorge Springs	Numerous hot springs in and adjacent to an approximately 1-km long reach of Hot Creek	93
7	Little Hot Creek Springs	Numerous hot springs that feed into Little Hot Creek	~80
8	Well MBP-3	Geothermal production well at Casa Diablo	161
9	Wells SC-1, SC-2	Wells near Sherwin Creek Campground	17
10	Mammoth Creek at Hwy 395	Site for chemical sampling and discharge measurements	17
11	Hot Creek above gorge	Site for chemical sampling and discharge measurements	~15
12	Hot Creek at Flume	Site for chemical sampling and discharge measurements	~35
13	LVEW	Site of Long Valley Exploration Well and adjacent water-supply well (SF) used for continuous pressure monitoring	100
14	LKT Well	Well near Lookout Mountain used for continuous pressure monitoring	--
15	RDO-8	Well near Shady Rest Campground used for continuous pressure monitoring	202
16	CH10-B Well	Well near Hot Creek Gorge used for continuous pressure monitoring	95
17	CW-3	Chance Well #3 near Hot Bubbling Pool	120