A new view of earthquake and volcano precursors

Abstract

A close coupling between monitoring and modeling is needed for a quantitative prediction of volcanic eruption and earthquake occurrence. The need is demonstrated for the volcano, Piton de la Fournaise, for which a relatively simple model can be constructed because of the isolated tectonic setting and can be tested in a short time because of the high rate of eruptions. Our conceptual model (Fig. 2) explains various observations for each of the 49 eruptions since 1972 in terms of the varying conditions of the model elements, allowing inferences on causal relations between consecutive eruptive periods, recognized as alternating active and quiet ones, as well as predictions on the possible eruption scenarios for the future. Lessons learned from the volcano are applied to earthquake prediction in California, and we found a model of earthquake loading process by plate-driving forces that can be effectively constrained by data from the existing seismic network. The model identified that the periods of several years preceding the 1952 Kern County earthquake and the 1989 Loma Prieta earthquake are in the anomalous phase of the loading process. A companion paper by Jin et al. (2004) in the present issue shows that the 1992 Landers earthquake and the 1999 Hector Mine earthquake were also preceded by the period of anomalous loading process.

High-resolution maps of Coda Q in Japan and their interpretation by the brittle-ductile interaction hypothesis

“…This is consistent with the brittle-ductile interaction hypothesis of earthquake loading by plate-driving forces proposed by Aki (2004) on the basis of three independent studies; global study of tectonic stress by Zoback and Zoback (2002), regional study of Iio et al (2002Iio et al ( , 2004, and the observed correlation between coda Q and N (M c ) by Jin andAki (1989, 1993). The occurrence of the Mw 6.8 central Niigata earthquake within the NKTZ in 2004 encourages further studies along this line.…”

“…Recently, Aki (2004) noticed that the simultaneous positive correlation between Q −1 c and N (M c ) obtained for the 50 year-period by Jin andAki (1989, 1993) for California, was disturbed for several years before the 1952 M7.5 earthquake, Kern County, California and the 1989 M7.1 earthquake, Loma Prieta, California. Jin et al (2004) extended the analyses of temporal variation of coda Q −1 and N (M c ) for central and southern California and applied a 10-year moving time window to calculate the cross-correlation between Q −1 c and N (M c ).…”

“…The disturbance is, consistently, a delay in the fluctuation of coda Q −1 relative to that of N (M c ) before the occurrence of a major earthquake. According to the "brittle-ductile interaction hy- pothesis" of earthquake loading processes by plate-driving forces proposed by Aki (2004), the coda Q −1 represents the density of the fractures in the ductile part of lithosphere, and N (M c ) represents the response of the brittle part to the stress induced by the ductile fracture. In the normal loading process the interaction between the ductile and brittle parts of the lithosphere is harmonic leading to the simultaneous positive correlation between coda Q −1 and N (M c ).…”

Numerical Study on a Relationship between Scattering Seismic Wave and Crustal Stress Filed, and its Possibility of Application to Field Data

“…Some papers reported anomalous value of Q c around volcanoes, faults 5) , which means the media has anomalous inhomogeneity. Also the recent results 4) reported that anomalous value of Q c was detected after a large earthquake. These results suggest that the order of inhomogeneities may vary in the course of long-term earthquake generation cycle, i.e., before and after the failure of crustal material takes place.…”

“…The cracks opened or closed by the stress change are one of the major factors which change the property of the crust. Jin et al (2004) 3) and Aki (2004) 4) proposed a "Brittle-Ductile Hypothesis" after a long-term observation of the seismicity around the San Andreas Fault that has led them to find a high correlation with Q c .…”