Mian Liu

• University of Georgia

Periodic or quasiperiodic earthquake recurrence on individual faults, as predicted by the elastic rebound model, is not common in nature. Instead, most earthquake sequences are complex and variable, and often show clusters of events separated by long but irregular intervals of quiescence. Such temporal patterns are especially common for large earth...

Long records often show large earthquakes occurring in supercycles, sequences of temporal clusters of seismicity, cumulative displacement, and cumulative strain release separated by less active intervals. Supercycles and as- sociated earthquake clusters are only partly characterized via the traditionally used aperiodicity, which mea- sures the exte...

The discovery of plate tectonics in the 1960s offered the promise of a physical foundation for earthquake hazard assessment. In subsequent years, knowledge of the geometry and rates of plate motions has improved dramatically, in part due to the advent of space-based geodesy and recognition that many plate boundaries are diffuse zones. In addition,...

Large earthquakes in North China, Australia, Northwestern Europe, Central and Eastern United States, and other mid-continents show complex spatiotemporal patterns that do not fit existing earthquake models. Individual faults or fault zones tend to fall into long term (thousands of years or longer) dormancy after a cluster of ruptures, whereas large...

The stable Ordos Plateau, extensional Weihe Graben, and Qinling orogenic belt are located at the northeast margin of the Tibetan Plateau. They have been thought to play different roles in the eastward expanding of the Tibetan Plateau. Peking University deployed a linear seismic array across the western end of the Weihe Graben to investigate the cru...

The 2013 Lushan earthquake illustrates once again the difficulties of earthquake prediction; it occurred without warning, whereas the entire Longmenshan fault zone has been under intensive study following the 2008 Wenchuan earthquake. Nonetheless, we find that studies of stress changes and seismic-moment releases in the aftermath of the Wenchuan ea...

The 2011 Tohoku earthquake is another striking example – after the 2008 Wenchuan and 2010 Haiti earthquakes – of highly destructive earthquakes that occurred in areas predicted by earthquake hazard maps to be relatively safe. Here, we examine what went wrong for Tohoku, and how this failure illustrates limitations of earthquake hazard mapping. We u...

O-Linked glycosylation is a functionally and structurally diverse type of protein modification present in many tissues and across many species. α-Dystroglycan (α-DG), a protein linked to the extracellular matrix, whose glycosylation status is associated with human muscular dystrophies, displays two predominant types of O-glycosylation, O-linked man...

Mucin glycoproteins present a complex structural landscape arising from the multiplicity of glycosylation patterns afforded by their numerous serine and threonine glycosylation sites, often in clusters, and with variations in respective glycans. To explore the structural complexities in such glycoconjugates, we used NMR to systematically analyze th...

Fault interaction is believed to influence seismicity and crustal deformation, but the mechanics of fault interaction over various time scales remain poorly understood. We present here a numerical investigation of fault coupling and interaction over multiple time scales, using the San Andreas fault and the San Jacinto fault in southern California a...

Sulfated glycolipids (SGs) and glycosaminoglycans (GAGs) present on the surface of colonic, vaginal epithelial and neuroglial cells bind to HIV GP120, suggesting that these glycoconjugates may have a role in HIV infection. The main goal of this work was to test the ability of the human milk glycoconjugates (SGs and GAGs) to inhibit the infection of...

Aberrant glycosylation of α-dystroglycan (α-DG) results in loss of interactions with the extracellular matrix and is central to the pathogenesis of several disorders. To examine protein glycosylation of α-DG, a facile synthetic approach has been developed for the preparation of unusual phosphorylated O-mannosyl glycopeptides derived from α-DG by a...

Dystroglycanopathies are a subset of congenital muscular dystrophies wherein α-dystroglycan (α-DG) is hypoglycosylated. α-DG is an extensively O-glycosylated extracellular matrix-binding protein and a key component of the dystrophin-glycoprotein complex. Previous studies have shown α-DG to be post-translationally modified by both O-GalNAc- and O-ma...

The Chinese mainland features widespread active faults and intensive seismic activity; both can be described in terms of slip rates on these faults. Previous studies of fault slip rates in mainland China have focused on individual faults or fault segments, and large discrepancies exist among results derived from different methods. Here we derive a...

Introduction: The lithosphere, which includes the crust and the uppermost part of the mantle, is the mechanically strong outer shell of the Earth. The lithosphere is broken into a dozen or so pieces, called the tectonic plates. Constant motions between these tectonic plates cause lithospheric deformation, which leads to mountain building, earthquak...

Aftershocks are smaller earthquakes following the mainshock. They typically occur on or near the rupture plane of the mainshock, resulting from changes of stress and frictional properties of the fault zone caused by the mainshock. The duration of aftershock sequences is typically a few years for earthquakes at plate boundaries, but can last much lo...

Glycoproteins are a major class of glycoconjugates displaying a variety of mutual interactions between glycan and protein moieties that ultimately affect molecular organization. Modulation of the pendant glycan structures is important in tuning the functions of glycoproteins. Here we discuss structural aspects and some of the challenges to studying...

Located at the northeastern margin of the Tibetan plateau, the Ordos block is a stable tectonic unit in North China. With its active boundary fault zones, the Ordos block played an important role in the eastward extrusion mechanism of the Tibetan plateau. Peking University deployed a linear array of 15 portable broadband seismometers across the wes...

A cyclic heptapeptide, c(Gly-Ile-Pro-Tyr-Ile-Ala-Ala), which was isolated and identified from Stellaria yumumensis French (M), was synthesized by solution method for the first time. Protected heptapeptide Z-Gly-Ile-Pro-Tyr-Ile-Ala-Ala-OBzl was synthesized with 3-(diethoxy-phosphoryloxy)-l,2,3-benzotriazin-4(3H)-one (DEPBT) as a coupling reagent. Af...

Three 18-residue peptides with the sequence Glp-Asp-Thr-Thr-Asp-Glu-Trp-Asp-Arg-Asp-Leu-Glu-Asn-Leu-Ser-Thr-Thr-Lys, taken from the N-terminus of the rat epididymal cysteine-rich secretory protein (Crisp-1) that is important in the fertilization process, were prepared by Fmoc solid-phase synthesis using a convergent strategy. These peptides were th...

The 12 May 2008 Wenchuan earthquake (Ms 8.0) occurred on the Longmen Shan fault zone, where slip rates are low and earthquakes are infrequent in comparison with other major fault zones in the Songpan-Ganze region, eastern Tibet. We have investigated the evolution of strain energy along major faults in this region by comparing the accumulation and r...

The 12 May 2008 Wenchuan earthquake (Mw 7.9) ruptured ∼ 300 km of the Longmen Shan fault, claiming ∼ 90,000 lives and devastating many cities in the Sichuan province, China. The coseismic stress changes due to the Wenchuan earthquake have been studied in kinematic models using the inferred coseismic fault slips, but the cause of the fault slips, th...

The San Andreas Fault (SAF) is the transform boundary between the Pacific and the North American plates, yet up to 25% of the relative plate motion is now accommodated by the eastern California shear zone (ECSZ). Here we investigate the inception of the ECSZ and its geodynamic interactions with the SAF using a 3-D viscoelastoplastic finite element...

There are several major active fault zones in the western Sichuan and its vicinity. Slip rates and seismicity vary on different fault zones. For example, slip rates on the Xianshuihe fault zone are higher than 10 mm/a. Its seismicity is also intense. Slip rates on the Longmenshan fault zone are low. However, Wenchuan M s8.0 earthquake occurred on t...

Thioester method for the synthesis of cyclopeptides is improved by using Pac (Pac = phenacyl, CH2COC6H5) ester as a protecting group of 3-mercaptopropionic acid. The Pac group is easy to be removed from C-terminal with zinc in acetic acid. The protected glycine thioester and peptide thioesters synthesized by the improved method, are easy to be puri...

The San Andreas Fault (SAF) is the transform boundary between the Pacific and the North American plates, yet up to 25% of the relative plate motion is now accommodated by the Eastern California Shear Zone (ECSZ). We have investigate the inception and development of the ECSZ and its geodynamic interactions with the SAF using a three-dimensional visc...

Plate tectonic theory provides a good sense of where to expect future large earthquakes on plate boundaries, and of the average time between them. However, no comparable model applies in continental interiors, where damaging earthquakes often pop up in unexpected places. This is well illustrated by the 2000-year record of earthquakes in North China...

The driving forces for crustal deformation are often inferred from the crustal kinematics. In the Southwestern United States, however, crustal kinematics delineated by the Global Positioning System (GPS) measurements differs significantly from that reconstructed from the geological records. This discrepancy is likely due to the different timescales...

Structural phase transitions of Zn4Sb3 and its substitutional compounds (Zn0.98M0.02)4Sb3 (M = Al, Ga and In) are investigated by electrical transport measurement and differential scanning calorimetry below room temperature. The results indicate that both beta --> alpha and alpha --> alpha' phase transitions of Zn4Sb3 are reversible and exothermic...

1] The enigmatic seismicity in the New Madrid Seismic Zone (NMSZ) has been attributed to some abnormal lithospheric structure, including the presence of dense mafic intrusions and a low-viscosity lower crust. However, the area's detailed lithospheric structure remains unclear. Here we invert 2,056 teleseismic P and 12,226 local P first arrival time...

Subduction-induced crustal shortening, now measured by the GPS across many subduction zones, has led to mountain building in the Andes but not in Cascadia and some other Andean-type convergent plate boundaries. Here we use a two-dimensional viscoelastoplastic finite element model to explore how the GPS-measured short-term strain relates to long-ter...

Subduction-induced crustal shortening is believed to be the primary cause of the Andean mountain building. The present-day crustal shortening in the Andes is clear from the GPS measurements, but the rate (30-40 mm/a) is higher than the geological shortening rate (<15 mm/a), suggesting that much of the present-day crustal shortening may recover duri...

Hydroxyl radical footprinting is a technique for studying protein structure and binding that entails oxidizing a protein system of interest with diffusing hydroxyl radicals, and then measuring the amount of oxidation of each amino acid. One important issue in hydroxyl radical footprinting is limiting amino acid oxidation by secondary oxidants to pr...

The ∼ 2000 km crustal shortening from the Indo-Asian collision in the past 40–70 million years has been accommodated mainly by crustal thickening in the Himalayan–Tibetan Plateau and lateral extrusion of blocks of Asian continents. However, the spatiotemporal evolution of crustal thickening and lateral extrusion, hence the far-field impact of the I...

Continental intraplate seismicity seems often episodic, clustered, and mi-grating. The observed seismicity shows both spatial clustering in seismic zones and scattering across large plate interiors, temporal clustering followed by long periods of quiescence, and migration of seismicity from one seismic zone to another. Here, we explore the complex...

The geometrical complexity of non-planar faults is known to affect not only fault slip rates but also crustal deformation and seismicity in the surrounding region, but implementing non-planar faults in numerical models has been challenging. We have developed a 3-D viscoelastoplastic finite element model to simulate long-term, steady-state fault sli...

UDP-GalNAc:polypeptide alpha-N-Acetylgalactosaminyltransferases (ppGalNAcTs), a family (EC 2.4.1.41) of enzymes that initiate mucin-type O-glycosylation, are structurally composed of a catalytic domain and a lectin domain. Previous studies have suggested that the lectin domain modulates the glycosylation of glycopeptide substrates and may underlie...

We have developed and validated a practical high-performance liquid chromatography method to determine the concentration of N-diisopropyloxyphosphoryl-valine-phenylalanine-3, 4, 5-trimethoxy aniline (DIPP-Val-Phe-TMOA) in Adriamycin-resistant human breast adenocarcinoma (MCF-7/ADR) cells. First, DIPP-Val-Phe-TMOA was extracted from MCF-7 cells with...

With the goal to investigate the structural impact of O‐mannosyl glycosylation on α‐dystroglycan, a glycoprotein that has an important role in the extracellular organization of muscle, glycopeptides derived from its mucin‐like sequence have been prepared by solid‐phase peptide synthesis. Two approaches have been explored to obtain needed mannosylat...

The San Andreas Fault (SAF) is the Pacific-North American plate boundary, yet in southern California a significant portion of the relative plate motion is accommodated by the San Jacinto Fault (SJF). Here we investigate the initiation of the SJF and its interaction with the SAF in a three-dimensional visco-elasto-plastic finite-element model. The m...

Lithospheric deformation in the western United States is one of the best examples of diffuse continental tectonics that deviate from the plate tectonics paradigm. Conceptually, diffuse continental deformation is known to result from (1) weak and heterogeneous rheology of continents and (2) driving forces that arise from plate boundaries as well as...

Software for geodynamic modeling has not kept up with the fast growing computing hardware and network resources. In the past decade supercomputing power has become available to most researchers in the form of affordable Beowulf clusters and other parallel computer platforms. However, to take full advantage of such computing power requires developin...

China is a country of intense intracontinental seismicity. Most earthquakes in west-ern China occur within the diffuse Indo-Eurasian plate-boundary zone, which extends thousands of kilometers into Asia. Earthquakes in eastern China mainly occur within the North China block, which is part of the Archean Sino-Korean craton that has been thermally rej...

A practical method for the analysis of genipin-1-β-gentiobioside in gardenia fruit was developed by high-performance liquid chromatography with ultraviolet monitoring and electrospray ionization mass spectrometry characterization (HPLC/UV/ESI-MS). Efficiency of ultrasonic extraction (UE), accelerated solvent extraction (ASE) and high-speed homogeni...

Most large earthquakes in northern and central California clustered along the main trace of the San Andreas Fault (SAF), the North American-Pacific plate boundary. However, in southern California earthquakes were rather scattered. Here we suggest that such along-strike variation of seismicity may largely reflect the geometrical impact of the SAF. U...

Solid-phase synthesis of mucin glycopeptides is an effective way to prepare constructs in order to investigate their biological and biophysical properties. This review highlights three key aspects of this process. First, methods to prepare α-glycosylated Thr and Ser derivatives as building blocks are outlined, including comparisons of the effects o...

The glycopeptide, Ac-Pro-Thr(alpha-D-GalNAc)-Thr(alpha-D-GalNAc)-Thr(alpha-d-GalNAc)-Pro-Leu-Lys-NH(2) (1), which features three consecutive O-glycosylated Thr residues and mimics a portion of mucin 2, has been prepared by solid-phase synthesis. Seven related, partially glycosylated peptides (2-8) were synthesized as well. This suite of molecules a...

The north China block (NCB), part of the Sino-Korean craton, is surprisingly one of the most active seismic regions in the world. The south China block (SCB), another major craton in East Asia, has been seismically quiescent. Using the updated GPS data and finite element modeling, we show that the kinematic boundary conditions are the primary cause...

1] Following a series of large (Mw = 7.0 – 7.5) earthquakes in the New Madrid Seismic Zone (NMSZ) in the central US during 1811 and 1812, more than a dozen moderate-size (M > 5) earthquakes occurred in this region, but mostly outside of the NMSZ fault zone. We have simulated the evolution of Coulomb stress and strain energy in the NMSZ and surround...

T(N) antigen building blocks Nalpha-(9-fluorenylmethoxycarbonyl)-O-(3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosyl)-L-serine/L-threonine pentafluorophenyl ester [Fmoc-L-Ser/L-Thr(Ac3-alpha-D-GalN3)-OPfp, 13/14] have been synthesized by two different routes, which have been compared. Overall isolated yields [three or four chemical steps...

The Indo–Asian continental collision is known to have had a great impact on crustal deformation in south-central Asia, but its effects on the sublithospheric mantle remain uncertain. Studies of seismic anisotropy and volcanism have suggested that the collision may have driven significant lateral mantle flow under the Asian continent, similar to the...

The Tarim basin in NW China developed as a complex foreland basin in the Cenozoic in association with mountain building in the Tibetan Plateau to the south and the Tian Shan orogen to the north. We reconstructed the Cenozoic deformation history of the Tarim basement by backstripping the sedimentary rocks. Two-dimensional and three-dimensional finit...

We investigated the macroscale fluid flow and oxygen isotope exchange in contact-metamorphic aureoles by using two-dimensional finite-element modeling. The model parameters are assigned according to geologic observations in the Notch Peak metamorphic aureole, Utah. The results show that fluid flow in contact aureoles depends strongly on time and sp...

Systematic discrepancies between the Global Positioning System (GPS) site velocities and those predicted by plate-motion models across the Andes, the Himalayan-Tibetan plateau, and the Taiwan orogen delineate diffuse plate-boundary deformation and significant intraplate deformation, even in the presumably rigid oceanic plates. The relationship betw...

The Mw=7.7 Republic Day (01/26/2001) earthquake near Bhuj in western In-dia killed nearly 20,000 people and destroyed tens of thousands of homes. The cause and the tectonic implication of this earthquake have been the subject of in-tensive debate. Located ~400 km from the plate boundary, the Bhuj earthquake bears significant similarities with some...

We have investigated the control of layered and transient permeability structures on fluid flow and thermal evolution in contact metamorphic aureoles using two-dimensional numerical modeling with petrological and geochemical constraints from the Notch Peak aureole, Utah. The model includes interbedded aquitard and aquifer lithologies on the scale o...

GPS data indicate 30-40 mm yr-1 present-day crustal shortening across the Andes, whereas geological evidence shows crustal shortening concentrated in the sub-Andean thrust belt at a much lower rate (<15 mm yr-1). We reconcile the discrepancy between the geodetic and the geological crustal shortening using geodynamic modeling that includes timescale...

Although gravitational collapse has been widely accepted as a viable explanation for both synorogenic and postorogenic extension, its mechanisms have not been well understood. Previous models of continental deformation that assumed a viscous or viscoplastic rheology are not well suited for simulating stress states and brittle deformation within the...

Leucogranites are common features of convergent orogens. However, the heat necessary for producing leucogranite magma from pelitic sources in convergent orogens is a major unresolved issue. We suggest that the generation of the Harney Peak Granite, Black Hills, South Dakota, during the Proterozoic Trans-Hudson orogeny is best explained by shear hea...

Gravitational collapse has been suggested as the major cause of Cenozoic extension in the North American Cordillera and many other orogenic belts. Although both crustal thickening and mantle upwelling may have contributed to the Cordilleran extension, previous models of gravitational collapse have focused on the former; the cause of mantle upwellin...

Intrusion and underplating of mafic magmas tend to facilitate continental extension by thermatically weakening the lithosphere. However, adding rheologically hard mafic material to the crust also strengthens the lithosphere. We have investigated the time-dependent competing effects of thermal weakening and rheological hardening using a simple numer...

Metamorphic core complexes in the southeastern Canadian Cordillera were formed during Eocene crustal extension, shortly (within a few millions of years) after Late Jurassic-Paleocene crustal shortening. Thermal-rheological modeling, constrained by geological and geochronological studies of the Valhalla core complex and other core complexes in this...

Results of numerical simulations of Cenozoic volcanism in the Coast Ranges of California, associated with the northward migration of the Mendocino Triple Junction (MTJ), are presented. Three aspects of the thermal evolution and magmatism in the wake of the MTJ are investigated: mantle flow and thermal perturbation in the 'slabless window'; pressure...

1] Following their initial collision 50–70 Myr ago, the Indian and Eurasian plates have been continuously converging toward each other. Whereas the regional stress field is predominately compressive, the Late Cenozoic tectonics within the Tibetan Plateau features widespread crustal extension. Numerous causes of the extension have been proposed, but...