Magmatic Resurgence in Long Valley Caldera, California: Possible Cause of the 1980 Mammoth Lakes Earthquakes

Savage, J. C.; Clark, Malcolm M.

doi:10.1126/science.217.4559.531

Cited by 158 publications

(82 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At very large calderas like Yellowstone, active deformation rates as high as 2.7 cm/year have been reported based on precise leveling measurements (Pelton and Smith, 1979;Jackson et al, 1984), but such uplift is spatially and temporally variable and limited, and subsidence has also been recorded (Smith and Braile, 1994;Dzurisin et al, 1999). Maximum resurgence rates reported for Long Valley caldera are as high as 5 cm/year (Savage and Clark, 1982) and the most recent seismic unrest resulted in uplift of 80 cm, at an average rate of 3.8 cm/year (Sorey et al, 2003). "Restlessness" at Yellowstone and Long Valley is occurring 600-700 ka after the last major eruptions at these calderas.…”

Section: Introductionmentioning

confidence: 99%

Resurgent Tobaâ€”field, chronologic, and model constraints on time scales and mechanisms of resurgence at large calderas

et al. 2015

View full text Add to dashboard Cite

Highlights• New data reveal for the first time a history of the last ∼33.7 ky of uplift of Samosir.• Minimum uplift rates were high (4.9 cm/year) for the first 11.2 ky but diminished after that to <1 cm/year for the last 22.5 ky.• Numerical modeling suggests that rebound of remnant magma augmented by deep recharge appears to be the most likely driver for uplift.• Detumescence makes a negligible contribution to resurgent uplift.• The volume of the resurgent dome is isostatically compensated by magma • Average rates of uplift at Toba are much lower than currently restless calderas indicating a distinction between resurgence and "restlessness".New data reveal details of the post-caldera history at the Earth's youngest resurgent supervolcano, Toba caldera in Sumatra. Resurgence after the caldera-forming ∼74 ka Youngest Toba Tuff eruption uplifted the caldera floor as a resurgent dome, Samosir Island, capped with 100 m of lake sediments. 14 C age data from the uppermost datable sediments reveal that Samosir Island was submerged beneath lake level (∼900 m a.s.l) at 33 ka. Since then, Samosir experienced 700 m of uplift as a tilted block dipping to the west. 14 C ages and elevations of sediment along a transect of Samosir reveal that minimum uplift rates were ∼4.9 cm/year from ∼33.7 to 22.5 ka, but diminished to ∼0.7 cm/year after 22.5 ka. Thermo-mechanical models informed by these rates reveal that detumescence does not produce the uplift nor the uplift rates estimated for Samosir. However, models calculating the effect of volume change of the magma reservoir within a temperature-dependent viscoelastic host rock reveal that a single pulse of ∼475 km 3 of magma produces a better fit to the uplift data than a constant flux. The cause of resurgent uplift of the caldera floor is rebound of remnant magma as the system re-established magmastatic and isostatic equilibrium after the caldera collapse. Previous assertions that the caldera floor was apparently at 400 m a.s.l or lower requires that uplift must have initiated between sometime between 33.7 and 74 ka at a minimum average uplift rate of ∼1.1 cm/year. The change in uplift rate from pre-33.7 ka to immediately post-33.7 ka suggests a role for deep recharge augmenting rebound. Average minimum rates of de Silva et al.Resurgence at Toba caldera, Sumatra resurgent uplift at Toba are at least an order of magnitude slower than net rates of "restlessness" at currently active calderas. This connotes a distinction between resurgence and "restlessness" controlled by different processes, scales of process, and controlling variables.

show abstract

Section: Introductionmentioning

confidence: 99%

Resurgent Tobaâ€”field, chronologic, and model constraints on time scales and mechanisms of resurgence at large calderas

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The 1997-1998 episode of seismic unrest was preceded by an upswing in deformation data that Langbein et al (1998) interpret in terms of an intrusion event under the resurgent dome as well as a component of strike-slip motion within the south moat. Such an event will clearly provide a source of regional strain (Savage and Clark, 1982). A spattering of regional seismicity-10 events with M 4.0-5.0 at distances of roughly 50-100 km of the caldera-occurred in 1997-1998 and is plausibly associated with this strain.…”

Section: Interpretation and Conclusionmentioning

confidence: 99%

“…A spattering of regional seismicity-10 events with M 4.0-5.0 at distances of roughly 50-100 km of the caldera-occurred in 1997-1998 and is plausibly associated with this strain. Savage and Clark (1982) showed that inflation beneath the resurgent dome would give rise to tensile stresses in the SNB region. The nature of the extensional processes in the SNB has been investigated recently via detailed seismotectonic analyses.…”

Section: Interpretation and Conclusionmentioning

confidence: 99%

“…The area has been monitored intensely since 1980, when the region was shaken by four M 6 earthquakes and many thousands of smaller events. Although geodetic data reveal that deformation since 1980 has been associated primarily with uplift of the resurgent dome (e.g., Savage and Clark, 1982;Langbein et al, 1995), most of the seismic-moment release associated with the 1980 sequence occurred not within the caldera, but within the Sierran Nevada block (SNB) immediately to the south-southeast (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

“…Because of the absence of both previous (recent) volcanism and present-day geothermal features, the SNB to the south-southeast of the caldera has generally been considered an unlikely candidate for volcanic activity in spite of its substantial recent earthquake activity. The seismic activity in this region has generally been regarded as tectonic, either an accommodation of strain resulting from inflation of the resurgent dome (Savage and Clark, 1982) or a reflection of the ongoing extensional tectonic processes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The 1998 Earthquake Sequence South of Long Valley Caldera, California: Hints of Magmatic Involvement

Hough

Dollar

Johnson

2000

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

A significant episode of seismic and geodetic unrest took place at Long Valley Caldera, California, beginning in the summer of 1997. Activity through late May of 1998 was concentrated in and around the south moat and the south margin of the resurgent dome. The Sierran Nevada block (SNB) region to the south/southeast remained relatively quiet until a M 5.1 event occurred there on 9 June 1998 (UT). A second M 5.1 event followed on 15 July (UT); both events were followed by appreciable aftershock sequences. An additional, distinct burst of activity began on 1 August 1998. The number of events in the August sequence (over the first week or two) was similar to the aftershock sequence of the 15 July 1998 M 5.1 event, but the later sequence was not associated with any events larger than M 4.3. All of the summer 1998 SNB activity was considered tectonic rather than magmatic; in general the SNB is considered an unlikely location for future eruptions. However, the August sequence-an "aftershock sequence without a mainshock"-is suggestive of a strain event larger than the cumulative seismotectonic strain release. Moreover, a careful examination of waveforms from the August sequence reveals a small handful of events whose spectral signature is strikingly harmonic. We investigate the waveforms of these events using spectral, autocorrelation, and empirical Green's function techniques and conclude that they were most likely associated with a fluid-controlled source. Our observations suggest that there may have been some degree of magma or magma-derived fluid involvement in the 1998 SNB sequence.

show abstract

From quiescence to unrest: 20 years of satellite geodetic measurements at Santorini volcano, Greece

et al. 2015

View full text Add to dashboard Cite

Periods of unrest at caldera-forming volcanic systems characterized by increased rates of seismicity and deformation are well documented. Some can be linked to eventual eruptive activity, while others are followed by a return to quiescence. Here we use a 20 year record of interferometric synthetic aperture radar (InSAR) and GPS measurements from Santorini volcano to further our understanding of geodetic signals at a caldera-forming volcano during the periods of both quiescence and unrest, with measurements spanning a phase of quiescence and slow subsidence (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), followed by a phase of unrest (January 2011 to April 2012) with caldera-wide inflation and seismicity. Mean InSAR velocity maps from 1993-2010 indicate an average subsidence rate of~6 mm/yr over the southern half of the intracaldera island Nea Kameni. This subsidence can be accounted for by a combination of thermal contraction of the 1866-1870 lava flows and load-induced relaxation of the substrate. For the period of unrest, we use a joint inversion technique to convert InSAR measurements from three separate satellite tracks and GPS observations from 10 continuous sites into a time series of subsurface volume change. The optimal location of the inflating source is consistent with previous studies, situated north of Nea Kameni at a depth of~4 km. However, the time series reveals two distinct pressure pulses. The first pulse corresponds to a volume change (ΔV) within the shallow magma chamber of (11.56 ± 0.14) × 10 6 m 3 , and the second pulse has a ΔV of (9.73 ± 0.10) × 10 6 m 3 . The relationship between the timing of these pulses and microseismicity observations suggests that these pulses may be driven by two separate batches of magma supplied to a shallow reservoir. We find no evidence suggesting a change in source location between the two pulses. The decline in the rates of volume change at the end of both pulses and the observed lag of the deformation signal behind cumulative seismicity, suggest a viscoelastic response. We use a simple model to show that two separate pulses of magma intruding into a shallow magma chamber surrounded by a viscoelastic shell can account for the observed temporal variation in cumulative volume change and seismicity throughout the period of unrest. Given the similarities between the geodetic signals observed here and at other systems, this viscoelastic model has potential use for understanding behavior at other caldera systems.

show abstract

Magmatic Resurgence in Long Valley Caldera, California: Possible Cause of the 1980 Mammoth Lakes Earthquakes

Cited by 158 publications

References 8 publications

Resurgent Tobaâ€”field, chronologic, and model constraints on time scales and mechanisms of resurgence at large calderas

Resurgent Tobaâ€”field, chronologic, and model constraints on time scales and mechanisms of resurgence at large calderas

The 1998 Earthquake Sequence South of Long Valley Caldera, California: Hints of Magmatic Involvement

From quiescence to unrest: 20 years of satellite geodetic measurements at Santorini volcano, Greece

Contact Info

Product

Resources

About