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Define the sums of triple reciprocals Zn=∑i+j+k=n1/ijk,i,j,k≥1. Zhao discovered the following curious congruence for any odd prime p, Zp≡−2Bp−3mod p. Xia and Cai extended the above congruence to modulo p2,Zp≡12Bp−3/p−3−3B2p−4/p−2mod p2, where p>5 is a prime. In this paper, we consider the congruences about Zp−1+N/N (where x is the integral part of x, N=1,2,3,4,6) modulo p2. When N=1, the results we obtain are the results of Zhao and Xia and Cai.

The Neogene Terror Rift in the Antarctic Victoria Land Basin (VLB) of the Ross Sea, Antarctica, is composed of the Discovery Graben and the Lee Arch. Many Neogene volcanoes are aligned in the north-south direction in the southern VLB, belonging to the McMurdo Volcanic Group. However, due to multiple glaciations and limited seismic data, the volcanic processes are still unclear in the northern VLB, especially in the Terror Rift. Multichannel seismic profiles were collected at the VLB from the 32nd Chinese National Antarctic Research Expedition (CHINARE). We utilized four seismic profiles from the CHINARE and additional historical profiles, along with gravity and magnetic anomalies, to analyze faults and stratigraphic characteristics in the northern Terror Rift and volcanism in the VLB. Negative flower structures found in the northern Terror Rift suggest that the Terror Rift was affected by dextral strike-slip faults extending from the northern Victoria Land (NVL). After the initial orthogonal tension, the rift transited into an oblique extension, forming a set of downward concaving normal faults and accommodation zones in the Terror Rift. On the Lee Arch, several imbricated normal faults formed and converged into a detachment fault. Under gravitational forces, the strata bent upward and formed a rollover anticline. Many deep faults and thin strata subjected to erosion facilitated volcanic activity. A brittle volcanic region in the VLB was affected by dextral strike-slip movements and east-west extension, resulting in two Neogene volcanic chains that connect three igneous provinces in the VLB: the Hallett, Melbourne, and Erebus Provinces. These two chains contain mud volcanoes with magnetic nuclei, volcanic intrusions, and late-stage volcanic eruptions. Volcanisms have brought about opposite polarities of magnetic anomalies in Antarctica, indicating the occurrence of multiple volcanic activities.

Abstract Marine gravimeter has been proved to be the primary technique to efficiently obtain middle-to-short wavelength signals of the earth’s gravity field in geodesy, geodynamics and marine sciences research. In recent years, some prototypes of inertial platform and strapdown marine gravimeters have been developed, where the inertial platform gravimeter systems include CHZ-II and ZL11, and strapdown gravimeter systems include SAG-2M and SGA-WZ. In order to validate the performance of these marine gravimeter prototypes, a synchronous test with the widely used gravimeters GT-2M and LCR arranged on the same vessel was carried out in the north of South China Sea. All the data are processed according to the survey standard flow, and the performance is estimated by analyzing the errors of the repeat lines and the crossover points under the same environment. The compared results show that all the six gravimeters can meet the precision requirement of marine gravity survey. Meanwhile, the precision results of the improved gravimeters can get close to the precision of gravimeter GT-2M, higher than the precision gravimeter LCR.

We conducted a 9-d seismic experiment in October 2015 at Laohugou Glacier No. 12. We identified microseismic signals using the short-term/long-term average trigger algorithm at four stations and classified them as long and short-duration events based on waveform, frequency, duration and magnitude characteristics. Both categories show systematical diurnal trends. The long-duration events are low-frequency tremor-like events that mainly occurred during the daytime with only several events per day. These events lasted tens of seconds to tens of minutes and are likely related to resonance of daytime meltwater. The dominant short-duration events mostly occurred during the night time with a peak occurrence frequency of ~360 h−1. Their short-duration (