Table 2.

Characteristics of injection wells/leases in selected regions. Table values are number of permitted wells/leases; values in the “near earthquake (EQ)” column are number of wells where this study identified A-quality earthquake epicenters within 5 km; remaining columns are number of wells where maximum monthly injection rate between October 2006 and September 2011 exceeded specified value. Units for injection rates are barrels of water per month (BWPM); 1500 BWPM is 240 m³/mo

Geographic region	near EQ	> 150,000 BWPM	> 15,000 BWPM	> 1500 BWPM
Parker County	0	14	20	24
Stephens County	0	24	77	165
Tarrant County	1	8	8	8
Wise County	3	9	27	36
Johnson County	9	27	27	27
Seismic region (Fig. 2)	17	74	106	125
Barnett Shale (Figs. 1 and 5)	17	161	715	2,458
Texas		1,161	5,017	9,052