Mount St Helens
"Thrust Faults on the Crater Floor of Mount St. Helens, 1981: A Personal Account"

"Active Tectonics of the Los Angeles Basin" - Power Point presentation given at Caltech, October 2005. (Abstract)

Kashmir Earthquake of 8 October 2005, M 7.6
Tectonic setting of Balakot-Bagh fault (red line).  This fault cuts across the Hazara-Kashmir
syntaxis of Himalaya and follows the Indus-Kohistan Seismic Zone.  It was mapped by Geological Survey of Pakistan based on distribution of landslides and heavy damage, later substantiated by evidence of surface rupture (discussed below)

Location of Balakot-Bagh fault that ruptured in the M 7.6 earthquake of 8 October 2005 -
The rupture extended from the Northwest Frontier Province, where major damage was experienced at Balakot and Batagram, and the Pakistan sector of Kashmir, where major damage was sustained at Muzaffarabad and Bagh.

Radar data from the European Space Agency's environmental satellite, ENVISAT.  Two
radar images, one taken before and one after the earthquake, when superimposed, show the change in distance between the ground and the satellite between the two flights, assumed to be the coseismic displacement accompanying the earthquake.  The northeast side went up as much as 3 m (blue patches) in three different localities along the fault, shown here in red.  Image courtesy of COMET (Centre for the Observation and Modelling of Earthquakes and Tectonics, http://comet.nerc.ac.uk/news_kashmir.html

Coulomb stress change due to the 8 October 2005 M = 7.6 Kashmir earthquake, calculated by Tom Parsons, USGS, using a preliminary slip model by Yuji Yagi and an assumed hypocentral depth of 10 km.  40 days of aftershocks are shown.  Faults in heavy lines are from Yeats et al. (1992), Annales Tectonicae, Supplement to Volume VI.  Those in light red dashed lines are the major tectonic boundary faults of the Himalaya, which were not activated by the earthquake.  Stresses have increased to the northwest, in the vicinity of the Pattan earthquake of 1974, and to the southeast, where an earthquake of about the same size
struck Kashmir in 1885 and a larger earthquake of M>8 struck in 1555 according to Roger Bilham of the University of Colorado.  The earthquake might have struck the same zone of high seismicity that activated the 1905 Kangra, India, earthquake of M 7.8.  Note that stresses along the frontal Salt Range thrust (Yeats et al., 1984, GSA Bulletin) were not increased by the 2005 earthquake.

The slides below were taken first by Lt. Col. Wiley Thompson  and his colleagues on the U.S. Helicopter relief mission immediately after the earthquake, and on a subsequent visit to the earthquake area on 20-22 January, 2006 by Bob Yeats (USA), Takashi Nakata, Hiroyuki Tsutsumi, Yasuo Awata, and Heitaro Kaneda (Japan), and Ahmad Hussain, M. Shahid Baig,  Adnan Awan, Waliullah Khattak,  and Muhammad Ashraf (Pakistan); see abstract for affiliations.  Thompson photos are labeled WT, Yeats photos RY, and Nakata photos TN.  These are provided for teaching purposes only.  For use in any publication, a release must be obtained from the photographer

View northeast from hanging wall of Panjal thrust (MCT) to Subhimalaya underlain by Murree Formation (ridges in snow), showing the topographicc step across the Indus-Kohistan seismic Zone (IKSZ).  This relation is the opposite from India and Nepal, where the Subhimalaya is at low altitudes and the High Himalaya is in the hanging wall of the MCT.  This shows that the topographic break is related to the IKSZ and not the surface trace of the
MCT.  Photo by Robert Yeats (RY).

From the road to Balakot, the Balakot-Bagh fault is marked by landslides in limestone of the
Precambrian Muzaffarabad Formation.  (RY).

Earthquake triggered landslide into the Neelum River in Muzaffarabad; photo by Lt. Col. Wiley Thompson, PhD student at OSU who was part of the relief mission to Kashmir after the earthquake. This photo was published in the January 2006 Geotimes; subsequent photos by Wiley Thompson identified as WT. Rapids in Neelum River (lower right) formed by uplift along the hanging wall of a NE-striking lateral ramp of the surface rupture.  Trace the fault
down toward bottom of figure where it is marked by a scarp facing to the right, on which damage to houses was nearly total.  Damage farther away from fault was much less.

View northeast toward great Muzaffarabad landslide shown in previous slide, showing the active trace of the Balakot-Bagh fault, here probably a fold scarp, with the active zone at
the base.  Note the heavy damage to houses on the scarp relative to those on the downthrown block to the right. (RY)

Local people told us that this scarp appeared during the earthquake and thus was formed in 2005.  Possible trench site. (RY)

The 2005 fault/fold scarp, view to southwest.  (RY)

The 2005 rupture continued across the Neelum River, forming rapids.  These rapids are also visible in the aerial view photographed by Wiley Thompson, shown above.  View north. (RY)

View south across scarp (boulders at bottom of photo) to a fence that is offset left-laterally as well as vertically, indicating a left-lateral component on the lateral ramp in the Balakot-Bagh fault. (TN)

Mirza Shahid Baig, PhD Oregon State University, now Dean of Science at the University of Azad Jammu Kashmir at Muzaffarabad, with Bob Yeats.  Baig happened to step outside on the morning of October 8, so his life was spared when the earthquake destroyed his campus, including the Geology Department.  His department moved temporarily to Islamabad, and he
returned to the field to be the first to recognize surface rupture or a fold scarp, as illustrated above.

Large landslide triggered by the 8 October 2005 earthquake in Kashmir, Pakistan.  Hattian landslide into tributaries of Jhelum River southeast of Muzaffarabad.  The landslide covered a distance of 2.75 km in less than 30 seconds.  Bedrock of middle Cenozoic nonmarine redbeds of the Murree Formation. The landslide covered a distance of 2.75 km, from near the top of Dana Hill to small tributaries of the Jhelum River in less than 30 seconds.  At lower left, one of the tributaries was dammed by the slide, and a new lake is building up behind the slide.  The potential hazards here are (1) the lake will overtop the slide and discharge catastrophically into the Jhelum River, (2) water will penetrate the slide mass by piping and discharge downstream, and (3) a new slide into the lake will trigger a large wave that will overtop and cut into the dam.  Bedrock of middle Cenozoic nonmarine redbeds of the Murree Formation.  (WT); photo taken in mid-October before start of rainy season.

Headwall scarp of a slide mass that has not yet failed, pointing out the danger of a new slide producing a catastrophic wave in one of the slide-dammed lakes. (WT)

Note how momentum of slide carried the base uphill on the opposite side of the valley. (WT)

Close-up of bulbous base of slide where it has been carried across the valley.  (WT)

Damage to the town of Balakot, North-West Frontier Province of Pakistan due to the 8 October 2005 earthquake of M 7.6.  View northwest in town of Balakot, NWFP.  Isolated hill in middle distance is a faulted terrace of Kunhar River resting on Murree Formation.  Surface rupture follows the left (west) edge of hill, which provides evidence for prehistoric earthquakes prior to 2005. Damage to houses is near-total on top of the terrace.  The fault is traced to the river where it is marked by near-total damage to houses.  In the river, it is identified by rapids (lower left edge of photo).  (WT)

Between the high terrace and the Kunhar River, the surface trace cuts the road in several places.  View east.  (RY)

Another view of the fault cutting the road, farther east.  Photo by Takashi Nakata, Hiroshima Technical University (TN)

The scarp, probably here a fold scarp, crosses the low terrace north of the Kunhar River, here tilting a fountain in a well-built house.  (TN)

Concrete foundation warped over fold scarp; view toward N.  (TN)

Detail of high terrace of Kunhar River showing near-total destruction of houses on top of terrace to trace of surface rupture at left side; cultivated area is on left side of fault.  (WT)

South of Muzaffarabad, within Murree Formation,  2005 fault crosses side drainage, producing knickpoint. (TN)

View upstream to fault crossing stream bed and scarp flanking it on both sides.  (TN)