Tuesday, March 8, 2011
A foothill earthquake was heard, not felt, by employee-residents in El Portal shortly before 11 p.m. last night. The hypocenter was nearly 15 miles beneath the Bootjack-Darrah Road-Triangle Road area, west of the park toward Mariposa. This is down in the granite batholith that underlies the western metamorphic belt we see at the surface along much of Highway 49 south of Mariposa. Hearing the earthquake in Rancheria Flat may be helped by its location at the contact zone of the granite and the older metamorphic rock.
The river has been well above average for months now, and the weekend rain has brought the river up again. It was very turbid yesterday. Yosemite Valley got rain and now the snow cover is patchy. The average flow for the Valley's exit in early March is about 300 cfs; it's now running over 500 cfs.
El Portal's flowers are looking good with numerous species found in many sunny locations. Bird activity has picked up, with abundant noisy robins joining vocal titmice, Hutton's vireos, flickers, both towhees and more. Treefrogs are chorusing in various places, even in snowy terrain in the Valley and Foresta.
The summertime's Scorpio is high in the south before dawn. The ISS flies across our sky about 7:30 this evening; STS Discovery has de-coupled for the last time before returning to solid ground tomorrow.